Add m-esr52 at 52.6.0

42 files changed, 5199 insertions, 0 deletions

diff --git a/accessible/windows/msaa/ARIAGridAccessibleWrap.cpp b/accessible/windows/msaa/ARIAGridAccessibleWrap.cpp
new file mode 100644
index 000000000..04f7c112f
--- /dev/null
+++ b/accessible/windows/msaa/ARIAGridAccessibleWrap.cpp
@@ -0,0 +1,47 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ARIAGridAccessibleWrap.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// ARIAGridAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(ARIAGridAccessibleWrap,
+                             ARIAGridAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(ARIAGridAccessibleWrap,
+                         AccessibleWrap,
+                         ia2AccessibleTable)
+
+void
+ARIAGridAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTable::mTable = nullptr;
+  ARIAGridAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// ARIAGridCellAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(ARIAGridCellAccessibleWrap,
+                             ARIAGridCellAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(ARIAGridCellAccessibleWrap,
+                         HyperTextAccessibleWrap,
+                         ia2AccessibleTableCell)
+
+void
+ARIAGridCellAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTableCell::mTableCell = nullptr;
+  ARIAGridCellAccessible::Shutdown();
+}
diff --git a/accessible/windows/msaa/ARIAGridAccessibleWrap.h b/accessible/windows/msaa/ARIAGridAccessibleWrap.h
new file mode 100644
index 000000000..b03cc349f
--- /dev/null
+++ b/accessible/windows/msaa/ARIAGridAccessibleWrap.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef MOZILLA_A11Y_ARIAGRIDACCESSIBLEWRAP_H
+#define MOZILLA_A11Y_ARIAGRIDACCESSIBLEWRAP_H
+
+#include "ARIAGridAccessible.h"
+#include "ia2AccessibleTable.h"
+#include "ia2AccessibleTableCell.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * IA2 wrapper class for ARIAGridAccessible implementing IAccessibleTable and
+ * IAccessibleTable2 interfaces.
+ */
+class ARIAGridAccessibleWrap : public ARIAGridAccessible,
+                               public ia2AccessibleTable
+{
+  ~ARIAGridAccessibleWrap() {}
+
+public:
+  ARIAGridAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    ARIAGridAccessible(aContent, aDoc), ia2AccessibleTable(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+/**
+ * IA2 wrapper class for ARIAGridCellAccessible implementing
+ * IAccessibleTableCell interface.
+ */
+class ARIAGridCellAccessibleWrap : public ARIAGridCellAccessible,
+                                   public ia2AccessibleTableCell
+{
+  ~ARIAGridCellAccessibleWrap() {}
+
+public:
+  ARIAGridCellAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    ARIAGridCellAccessible(aContent, aDoc), ia2AccessibleTableCell(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/AccessibleWrap.cpp b/accessible/windows/msaa/AccessibleWrap.cpp
new file mode 100644
index 000000000..6112c370a
--- /dev/null
+++ b/accessible/windows/msaa/AccessibleWrap.cpp
@@ -0,0 +1,1686 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AccessibleWrap.h"
+#include "Accessible-inl.h"
+
+#include "Compatibility.h"
+#include "DocAccessible-inl.h"
+#include "mozilla/dom/TabChild.h"
+#include "mozilla/a11y/DocAccessibleChild.h"
+#include "mozilla/a11y/DocAccessibleParent.h"
+#include "EnumVariant.h"
+#include "nsAccUtils.h"
+#include "nsCoreUtils.h"
+#include "nsIAccessibleEvent.h"
+#include "nsWinUtils.h"
+#include "mozilla/a11y/ProxyAccessible.h"
+#include "ProxyWrappers.h"
+#include "ServiceProvider.h"
+#include "Relation.h"
+#include "Role.h"
+#include "RootAccessible.h"
+#include "sdnAccessible.h"
+#include "States.h"
+
+#ifdef A11Y_LOG
+#include "Logging.h"
+#endif
+
+#include "nsIMutableArray.h"
+#include "nsIFrame.h"
+#include "nsIScrollableFrame.h"
+#include "mozilla/dom/NodeInfo.h"
+#include "nsIServiceManager.h"
+#include "nsNameSpaceManager.h"
+#include "nsTextFormatter.h"
+#include "nsView.h"
+#include "nsViewManager.h"
+#include "nsEventMap.h"
+#include "nsArrayUtils.h"
+#include "mozilla/Preferences.h"
+#include "nsIXULRuntime.h"
+
+#include "oleacc.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+const uint32_t USE_ROLE_STRING = 0;
+
+/* For documentation of the accessibility architecture,
+ * see http://lxr.mozilla.org/seamonkey/source/accessible/accessible-docs.html
+ */
+
+//#define DEBUG_LEAKS
+
+#ifdef DEBUG_LEAKS
+static gAccessibles = 0;
+#endif
+
+MsaaIdGenerator AccessibleWrap::sIDGen;
+
+static const VARIANT kVarChildIdSelf = {VT_I4};
+
+static const int32_t kIEnumVariantDisconnected = -1;
+
+////////////////////////////////////////////////////////////////////////////////
+// AccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+AccessibleWrap::AccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+  Accessible(aContent, aDoc)
+  , mID(kNoID)
+{
+}
+
+AccessibleWrap::~AccessibleWrap()
+{
+  if (mID != kNoID) {
+    sIDGen.ReleaseID(this);
+  }
+}
+
+ITypeInfo* AccessibleWrap::gTypeInfo = nullptr;
+
+NS_IMPL_ISUPPORTS_INHERITED0(AccessibleWrap, Accessible)
+
+void
+AccessibleWrap::Shutdown()
+{
+  if (mID != kNoID) {
+    auto doc = static_cast<DocAccessibleWrap*>(mDoc.get());
+    MOZ_ASSERT(doc);
+    if (doc) {
+      doc->RemoveID(mID);
+      mID = kNoID;
+    }
+  }
+
+  Accessible::Shutdown();
+}
+
+//-----------------------------------------------------
+// IUnknown interface methods - see iunknown.h for documentation
+//-----------------------------------------------------
+
+// Microsoft COM QueryInterface
+STDMETHODIMP
+AccessibleWrap::QueryInterface(REFIID iid, void** ppv)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!ppv)
+    return E_INVALIDARG;
+
+  *ppv = nullptr;
+
+  if (IID_IUnknown == iid)
+    *ppv = static_cast<IAccessible*>(this);
+  else if (IID_IDispatch == iid || IID_IAccessible == iid)
+    *ppv = static_cast<IAccessible*>(this);
+  else if (IID_IEnumVARIANT == iid && !IsProxy()) {
+    // Don't support this interface for leaf elements.
+    if (!HasChildren() || nsAccUtils::MustPrune(this))
+      return E_NOINTERFACE;
+
+    *ppv = static_cast<IEnumVARIANT*>(new ChildrenEnumVariant(this));
+  } else if (IID_IServiceProvider == iid)
+    *ppv = new ServiceProvider(this);
+  else if (IID_ISimpleDOMNode == iid && !IsProxy()) {
+    if (IsDefunct() || (!HasOwnContent() && !IsDoc()))
+      return E_NOINTERFACE;
+
+    *ppv = static_cast<ISimpleDOMNode*>(new sdnAccessible(GetNode()));
+  }
+
+  if (nullptr == *ppv) {
+    HRESULT hr = ia2Accessible::QueryInterface(iid, ppv);
+    if (SUCCEEDED(hr))
+      return hr;
+  }
+
+  if (nullptr == *ppv && !IsProxy()) {
+    HRESULT hr = ia2AccessibleComponent::QueryInterface(iid, ppv);
+    if (SUCCEEDED(hr))
+      return hr;
+  }
+
+  if (nullptr == *ppv) {
+    HRESULT hr = ia2AccessibleHyperlink::QueryInterface(iid, ppv);
+    if (SUCCEEDED(hr))
+      return hr;
+  }
+
+  if (nullptr == *ppv && !IsProxy()) {
+    HRESULT hr = ia2AccessibleValue::QueryInterface(iid, ppv);
+    if (SUCCEEDED(hr))
+      return hr;
+  }
+
+  if (nullptr == *ppv)
+    return E_NOINTERFACE;
+
+  (reinterpret_cast<IUnknown*>(*ppv))->AddRef();
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+//-----------------------------------------------------
+// IAccessible methods
+//-----------------------------------------------------
+
+STDMETHODIMP
+AccessibleWrap::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *ppdispParent)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!ppdispParent)
+    return E_INVALIDARG;
+
+  *ppdispParent = nullptr;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  DocAccessible* doc = AsDoc();
+  if (doc) {
+    // Return window system accessible object for root document and tab document
+    // accessibles.
+    if (!doc->ParentDocument() ||
+        (nsWinUtils::IsWindowEmulationStarted() &&
+         nsCoreUtils::IsTabDocument(doc->DocumentNode()))) {
+      HWND hwnd = static_cast<HWND>(doc->GetNativeWindow());
+      if (hwnd && SUCCEEDED(::AccessibleObjectFromWindow(hwnd, OBJID_WINDOW,
+                                                         IID_IAccessible,
+                                                         (void**)ppdispParent))) {
+        return S_OK;
+      }
+    }
+  }
+
+  Accessible* xpParentAcc = Parent();
+  if (!xpParentAcc)
+    return S_FALSE;
+
+  *ppdispParent = NativeAccessible(xpParentAcc);
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accChildCount( long __RPC_FAR *pcountChildren)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pcountChildren)
+    return E_INVALIDARG;
+
+  *pcountChildren = 0;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  if (nsAccUtils::MustPrune(this))
+    return S_OK;
+
+  *pcountChildren = ChildCount();
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accChild(
+      /* [in] */ VARIANT varChild,
+      /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!ppdispChild)
+    return E_INVALIDARG;
+
+  *ppdispChild = nullptr;
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  // IAccessible::accChild is used to return this accessible or child accessible
+  // at the given index or to get an accessible by child ID in the case of
+  // document accessible.
+  // The getting an accessible by child ID is used by AccessibleObjectFromEvent()
+  // called by AT when AT handles our MSAA event.
+  bool isDefunct = false;
+  RefPtr<IAccessible> child = GetIAccessibleFor(varChild, &isDefunct);
+  if (!child) {
+    return E_INVALIDARG;
+  }
+
+  if (isDefunct) {
+    return CO_E_OBJNOTCONNECTED;
+  }
+
+  child.forget(ppdispChild);
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+/**
+ * This function is a helper for implementing IAccessible methods that accept
+ * a Child ID as a parameter. If the child ID is CHILDID_SELF, the function
+ * returns S_OK but a null *aOutInterface. Otherwise, *aOutInterface points
+ * to the resolved IAccessible.
+ *
+ * The CHILDID_SELF case is special because in that case we actually execute
+ * the implementation of the IAccessible method, whereas in the non-self case,
+ * we delegate the method call to that object for execution.
+ *
+ * A sample invocation of this would look like:
+ *
+ *  RefPtr<IAccessible> accessible;
+ *  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+ *  if (FAILED(hr)) {
+ *    return hr;
+ *  }
+ *
+ *  if (accessible) {
+ *    return accessible->get_accFoo(kVarChildIdSelf, pszName);
+ *  }
+ *
+ *  // Implementation for CHILDID_SELF case goes here
+ */
+HRESULT
+AccessibleWrap::ResolveChild(const VARIANT& aVarChild,
+                             IAccessible** aOutInterface)
+{
+  MOZ_ASSERT(aOutInterface);
+  *aOutInterface = nullptr;
+
+  if (aVarChild.vt != VT_I4) {
+    return E_INVALIDARG;
+  }
+
+  if (IsDefunct()) {
+    return CO_E_OBJNOTCONNECTED;
+  }
+
+  if (aVarChild.lVal == CHILDID_SELF) {
+    return S_OK;
+  }
+
+  bool isDefunct = false;
+  RefPtr<IAccessible> accessible = GetIAccessibleFor(aVarChild, &isDefunct);
+  if (!accessible) {
+    return E_INVALIDARG;
+  }
+
+  if (isDefunct) {
+    return CO_E_OBJNOTCONNECTED;
+  }
+
+  accessible.forget(aOutInterface);
+  return S_OK;
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accName(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszName)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszName || varChild.vt != VT_I4)
+    return E_INVALIDARG;
+
+  *pszName = nullptr;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accName(kVarChildIdSelf, pszName);
+  }
+
+  nsAutoString name;
+  Name(name);
+
+  // The name was not provided, e.g. no alt attribute for an image. A screen
+  // reader may choose to invent its own accessible name, e.g. from an image src
+  // attribute. Refer to eNoNameOnPurpose return value.
+  if (name.IsVoid())
+    return S_FALSE;
+
+  *pszName = ::SysAllocStringLen(name.get(), name.Length());
+  if (!*pszName)
+    return E_OUTOFMEMORY;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+
+STDMETHODIMP
+AccessibleWrap::get_accValue(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszValue)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszValue)
+    return E_INVALIDARG;
+
+  *pszValue = nullptr;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accValue(kVarChildIdSelf, pszValue);
+  }
+
+  nsAutoString value;
+  Value(value);
+
+  // See bug 438784: need to expose URL on doc's value attribute. For this,
+  // reverting part of fix for bug 425693 to make this MSAA method behave
+  // IAccessible2-style.
+  if (value.IsEmpty())
+    return S_FALSE;
+
+  *pszValue = ::SysAllocStringLen(value.get(), value.Length());
+  if (!*pszValue)
+    return E_OUTOFMEMORY;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accDescription(VARIANT varChild,
+                                   BSTR __RPC_FAR *pszDescription)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszDescription)
+    return E_INVALIDARG;
+
+  *pszDescription = nullptr;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accDescription(kVarChildIdSelf, pszDescription);
+  }
+
+  nsAutoString description;
+  Description(description);
+
+  *pszDescription = ::SysAllocStringLen(description.get(),
+                                        description.Length());
+  return *pszDescription ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accRole(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ VARIANT __RPC_FAR *pvarRole)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarRole)
+    return E_INVALIDARG;
+
+  VariantInit(pvarRole);
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accRole(kVarChildIdSelf, pvarRole);
+  }
+
+  a11y::role geckoRole;
+#ifdef DEBUG
+  NS_ASSERTION(nsAccUtils::IsTextInterfaceSupportCorrect(this),
+               "Does not support Text when it should");
+#endif
+
+  geckoRole = Role();
+
+  uint32_t msaaRole = 0;
+
+#define ROLE(_geckoRole, stringRole, atkRole, macRole, \
+             _msaaRole, ia2Role, nameRule) \
+  case roles::_geckoRole: \
+    msaaRole = _msaaRole; \
+    break;
+
+  switch (geckoRole) {
+#include "RoleMap.h"
+    default:
+      MOZ_CRASH("Unknown role.");
+  }
+
+#undef ROLE
+
+  // Special case, if there is a ROLE_ROW inside of a ROLE_TREE_TABLE, then call the MSAA role
+  // a ROLE_OUTLINEITEM for consistency and compatibility.
+  // We need this because ARIA has a role of "row" for both grid and treegrid
+  if (geckoRole == roles::ROW) {
+    Accessible* xpParent = Parent();
+    if (xpParent && xpParent->Role() == roles::TREE_TABLE)
+      msaaRole = ROLE_SYSTEM_OUTLINEITEM;
+  }
+
+  // -- Try enumerated role
+  if (msaaRole != USE_ROLE_STRING) {
+    pvarRole->vt = VT_I4;
+    pvarRole->lVal = msaaRole;  // Normal enumerated role
+    return S_OK;
+  }
+
+  // -- Try BSTR role
+  // Could not map to known enumerated MSAA role like ROLE_BUTTON
+  // Use BSTR role to expose role attribute or tag name + namespace
+  nsIContent *content = GetContent();
+  if (!content)
+    return E_FAIL;
+
+  if (content->IsElement()) {
+    nsAutoString roleString;
+    if (msaaRole != ROLE_SYSTEM_CLIENT &&
+        !content->GetAttr(kNameSpaceID_None, nsGkAtoms::role, roleString)) {
+      nsIDocument * document = content->GetUncomposedDoc();
+      if (!document)
+        return E_FAIL;
+
+      dom::NodeInfo *nodeInfo = content->NodeInfo();
+      nodeInfo->GetName(roleString);
+
+      // Only append name space if different from that of current document.
+      if (!nodeInfo->NamespaceEquals(document->GetDefaultNamespaceID())) {
+        nsAutoString nameSpaceURI;
+        nodeInfo->GetNamespaceURI(nameSpaceURI);
+        roleString += NS_LITERAL_STRING(", ") + nameSpaceURI;
+      }
+    }
+
+    if (!roleString.IsEmpty()) {
+      pvarRole->vt = VT_BSTR;
+      pvarRole->bstrVal = ::SysAllocString(roleString.get());
+      return S_OK;
+    }
+  }
+
+  return E_FAIL;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accState(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ VARIANT __RPC_FAR *pvarState)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarState)
+    return E_INVALIDARG;
+
+  VariantInit(pvarState);
+  pvarState->vt = VT_I4;
+  pvarState->lVal = 0;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accState(kVarChildIdSelf, pvarState);
+  }
+
+  // MSAA only has 31 states and the lowest 31 bits of our state bit mask
+  // are the same states as MSAA.
+  // Note: we map the following Gecko states to different MSAA states:
+  //   REQUIRED -> ALERT_LOW
+  //   ALERT -> ALERT_MEDIUM
+  //   INVALID -> ALERT_HIGH
+  //   CHECKABLE -> MARQUEED
+
+  uint64_t state = State();
+
+  uint32_t msaaState = 0;
+  nsAccUtils::To32States(state, &msaaState, nullptr);
+  pvarState->lVal = msaaState;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+
+STDMETHODIMP
+AccessibleWrap::get_accHelp(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszHelp)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszHelp)
+    return E_INVALIDARG;
+
+  *pszHelp = nullptr;
+  return S_FALSE;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accHelpTopic(
+      /* [out] */ BSTR __RPC_FAR *pszHelpFile,
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ long __RPC_FAR *pidTopic)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszHelpFile || !pidTopic)
+    return E_INVALIDARG;
+
+  *pszHelpFile = nullptr;
+  *pidTopic = 0;
+  return S_FALSE;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accKeyboardShortcut(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszKeyboardShortcut)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszKeyboardShortcut)
+    return E_INVALIDARG;
+  *pszKeyboardShortcut = nullptr;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accKeyboardShortcut(kVarChildIdSelf,
+                                               pszKeyboardShortcut);
+  }
+
+  KeyBinding keyBinding = AccessKey();
+  if (keyBinding.IsEmpty())
+    keyBinding = KeyboardShortcut();
+
+  nsAutoString shortcut;
+  keyBinding.ToString(shortcut);
+
+  *pszKeyboardShortcut = ::SysAllocStringLen(shortcut.get(),
+                                             shortcut.Length());
+  return *pszKeyboardShortcut ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accFocus(
+      /* [retval][out] */ VARIANT __RPC_FAR *pvarChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarChild)
+    return E_INVALIDARG;
+
+  VariantInit(pvarChild);
+
+  // VT_EMPTY:    None. This object does not have the keyboard focus itself
+  //              and does not contain a child that has the keyboard focus.
+  // VT_I4:       lVal is CHILDID_SELF. The object itself has the keyboard focus.
+  // VT_I4:       lVal contains the child ID of the child element with the keyboard focus.
+  // VT_DISPATCH: pdispVal member is the address of the IDispatch interface
+  //              for the child object with the keyboard focus.
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  // Return the current IAccessible child that has focus
+  Accessible* focusedAccessible = FocusedChild();
+
+  if (focusedAccessible == this) {
+    pvarChild->vt = VT_I4;
+    pvarChild->lVal = CHILDID_SELF;
+  }
+  else if (focusedAccessible) {
+    pvarChild->vt = VT_DISPATCH;
+    pvarChild->pdispVal = NativeAccessible(focusedAccessible);
+  }
+  else {
+    pvarChild->vt = VT_EMPTY;   // No focus or focus is not a child
+  }
+
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+/**
+ * This helper class implements IEnumVARIANT for a nsTArray containing
+ * accessible objects.
+ */
+class AccessibleEnumerator final : public IEnumVARIANT
+{
+public:
+  AccessibleEnumerator(const nsTArray<Accessible*>& aArray) :
+    mArray(aArray), mCurIndex(0) { }
+  AccessibleEnumerator(const AccessibleEnumerator& toCopy) :
+    mArray(toCopy.mArray), mCurIndex(toCopy.mCurIndex) { }
+  ~AccessibleEnumerator() { }
+
+  // IUnknown
+  DECL_IUNKNOWN
+
+  // IEnumVARIANT
+  STDMETHODIMP Next(unsigned long celt, VARIANT FAR* rgvar, unsigned long FAR* pceltFetched);
+  STDMETHODIMP Skip(unsigned long celt);
+  STDMETHODIMP Reset()
+  {
+    mCurIndex = 0;
+    return S_OK;
+  }
+  STDMETHODIMP Clone(IEnumVARIANT FAR* FAR* ppenum);
+
+private:
+  nsTArray<Accessible*> mArray;
+  uint32_t mCurIndex;
+};
+
+STDMETHODIMP
+AccessibleEnumerator::QueryInterface(REFIID iid, void ** ppvObject)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (iid == IID_IEnumVARIANT) {
+    *ppvObject = static_cast<IEnumVARIANT*>(this);
+    AddRef();
+    return S_OK;
+  }
+  if (iid == IID_IUnknown) {
+    *ppvObject = static_cast<IUnknown*>(this);
+    AddRef();
+    return S_OK;
+  }
+
+  *ppvObject = nullptr;
+  return E_NOINTERFACE;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleEnumerator::Next(unsigned long celt, VARIANT FAR* rgvar, unsigned long FAR* pceltFetched)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  uint32_t length = mArray.Length();
+  HRESULT hr = S_OK;
+
+  // Can't get more elements than there are...
+  if (celt > length - mCurIndex) {
+    hr = S_FALSE;
+    celt = length - mCurIndex;
+  }
+
+  // Copy the elements of the array into rgvar.
+  for (uint32_t i = 0; i < celt; ++i, ++mCurIndex) {
+    rgvar[i].vt = VT_DISPATCH;
+    rgvar[i].pdispVal = AccessibleWrap::NativeAccessible(mArray[mCurIndex]);
+  }
+
+  if (pceltFetched)
+    *pceltFetched = celt;
+
+  return hr;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleEnumerator::Clone(IEnumVARIANT FAR* FAR* ppenum)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  *ppenum = new AccessibleEnumerator(*this);
+  if (!*ppenum)
+    return E_OUTOFMEMORY;
+  NS_ADDREF(*ppenum);
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleEnumerator::Skip(unsigned long celt)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  uint32_t length = mArray.Length();
+  // Check if we can skip the requested number of elements
+  if (celt > length - mCurIndex) {
+    mCurIndex = length;
+    return S_FALSE;
+  }
+  mCurIndex += celt;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+/**
+  * This method is called when a client wants to know which children of a node
+  *  are selected. Note that this method can only find selected children for
+  *  accessible object which implement SelectAccessible.
+  *
+  * The VARIANT return value arguement is expected to either contain a single IAccessible
+  *  or an IEnumVARIANT of IAccessibles. We return the IEnumVARIANT regardless of the number
+  *  of children selected, unless there are none selected in which case we return an empty
+  *  VARIANT.
+  *
+  * We get the selected options from the select's accessible object and wrap
+  *  those in an AccessibleEnumerator which we then put in the return VARIANT.
+  *
+  * returns a VT_EMPTY VARIANT if:
+  *  - there are no selected children for this object
+  *  - the object is not the type that can have children selected
+  */
+STDMETHODIMP
+AccessibleWrap::get_accSelection(VARIANT __RPC_FAR *pvarChildren)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarChildren)
+    return E_INVALIDARG;
+
+  VariantInit(pvarChildren);
+  pvarChildren->vt = VT_EMPTY;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  if (IsSelect()) {
+    AutoTArray<Accessible*, 10> selectedItems;
+    SelectedItems(&selectedItems);
+
+    // 1) Create and initialize the enumeration
+    RefPtr<AccessibleEnumerator> pEnum = new AccessibleEnumerator(selectedItems);
+    pvarChildren->vt = VT_UNKNOWN;    // this must be VT_UNKNOWN for an IEnumVARIANT
+    NS_ADDREF(pvarChildren->punkVal = pEnum);
+  }
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::get_accDefaultAction(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszDefaultAction)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pszDefaultAction)
+    return E_INVALIDARG;
+
+  *pszDefaultAction = nullptr;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->get_accDefaultAction(kVarChildIdSelf, pszDefaultAction);
+  }
+
+  nsAutoString defaultAction;
+  ActionNameAt(0, defaultAction);
+
+  *pszDefaultAction = ::SysAllocStringLen(defaultAction.get(),
+                                          defaultAction.Length());
+  return *pszDefaultAction ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::accSelect(
+      /* [in] */ long flagsSelect,
+      /* [optional][in] */ VARIANT varChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->accSelect(flagsSelect, kVarChildIdSelf);
+  }
+
+  if (flagsSelect & SELFLAG_TAKEFOCUS) {
+    if (XRE_IsContentProcess()) {
+      // In this case we might have been invoked while the IPC MessageChannel is
+      // waiting on a sync reply. We cannot dispatch additional IPC while that
+      // is happening, so we dispatch TakeFocus from the main thread to
+      // guarantee that we are outside any IPC.
+      nsCOMPtr<nsIRunnable> runnable =
+        mozilla::NewRunnableMethod(this, &Accessible::TakeFocus);
+      NS_DispatchToMainThread(runnable, NS_DISPATCH_NORMAL);
+      return S_OK;
+    }
+    TakeFocus();
+    return S_OK;
+  }
+
+  if (flagsSelect & SELFLAG_TAKESELECTION) {
+    TakeSelection();
+    return S_OK;
+  }
+
+  if (flagsSelect & SELFLAG_ADDSELECTION) {
+    SetSelected(true);
+    return S_OK;
+  }
+
+  if (flagsSelect & SELFLAG_REMOVESELECTION) {
+    SetSelected(false);
+    return S_OK;
+  }
+
+  return E_FAIL;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::accLocation(
+      /* [out] */ long __RPC_FAR *pxLeft,
+      /* [out] */ long __RPC_FAR *pyTop,
+      /* [out] */ long __RPC_FAR *pcxWidth,
+      /* [out] */ long __RPC_FAR *pcyHeight,
+      /* [optional][in] */ VARIANT varChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pxLeft || !pyTop || !pcxWidth || !pcyHeight)
+    return E_INVALIDARG;
+
+  *pxLeft = 0;
+  *pyTop = 0;
+  *pcxWidth = 0;
+  *pcyHeight = 0;
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->accLocation(pxLeft, pyTop, pcxWidth, pcyHeight,
+                                   kVarChildIdSelf);
+  }
+
+  nsIntRect rect = Bounds();
+
+  *pxLeft = rect.x;
+  *pyTop = rect.y;
+  *pcxWidth = rect.width;
+  *pcyHeight = rect.height;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::accNavigate(
+      /* [in] */ long navDir,
+      /* [optional][in] */ VARIANT varStart,
+      /* [retval][out] */ VARIANT __RPC_FAR *pvarEndUpAt)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarEndUpAt)
+    return E_INVALIDARG;
+
+  VariantInit(pvarEndUpAt);
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varStart, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->accNavigate(navDir, kVarChildIdSelf, pvarEndUpAt);
+  }
+
+  Accessible* navAccessible = nullptr;
+  Maybe<RelationType> xpRelation;
+
+#define RELATIONTYPE(geckoType, stringType, atkType, msaaType, ia2Type) \
+  case msaaType: \
+    xpRelation.emplace(RelationType::geckoType); \
+    break;
+
+  switch(navDir) {
+    case NAVDIR_FIRSTCHILD:
+      if (IsProxy()) {
+        if (!Proxy()->MustPruneChildren()) {
+          navAccessible = WrapperFor(Proxy()->FirstChild());
+        }
+      } else {
+        if (!nsAccUtils::MustPrune(this))
+          navAccessible = FirstChild();
+      }
+      break;
+    case NAVDIR_LASTCHILD:
+      if (IsProxy()) {
+        if (!Proxy()->MustPruneChildren()) {
+          navAccessible = WrapperFor(Proxy()->LastChild());
+        }
+      } else {
+        if (!nsAccUtils::MustPrune(this))
+          navAccessible = LastChild();
+      }
+      break;
+    case NAVDIR_NEXT:
+      navAccessible = IsProxy()
+        ? WrapperFor(Proxy()->NextSibling())
+        : NextSibling();
+      break;
+    case NAVDIR_PREVIOUS:
+      navAccessible = IsProxy()
+        ? WrapperFor(Proxy()->PrevSibling())
+        : PrevSibling();
+      break;
+    case NAVDIR_DOWN:
+    case NAVDIR_LEFT:
+    case NAVDIR_RIGHT:
+    case NAVDIR_UP:
+      return E_NOTIMPL;
+
+    // MSAA relationship extensions to accNavigate
+#include "RelationTypeMap.h"
+
+    default:
+      return E_INVALIDARG;
+  }
+
+#undef RELATIONTYPE
+
+  pvarEndUpAt->vt = VT_EMPTY;
+
+  if (xpRelation) {
+    Relation rel = RelationByType(*xpRelation);
+    navAccessible = rel.Next();
+  }
+
+  if (!navAccessible)
+    return E_FAIL;
+
+  pvarEndUpAt->pdispVal = NativeAccessible(navAccessible);
+  pvarEndUpAt->vt = VT_DISPATCH;
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::accHitTest(
+      /* [in] */ long xLeft,
+      /* [in] */ long yTop,
+      /* [retval][out] */ VARIANT __RPC_FAR *pvarChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!pvarChild)
+    return E_INVALIDARG;
+
+  VariantInit(pvarChild);
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  Accessible* accessible = ChildAtPoint(xLeft, yTop, eDirectChild);
+
+  // if we got a child
+  if (accessible) {
+    // if the child is us
+    if (accessible == this) {
+      pvarChild->vt = VT_I4;
+      pvarChild->lVal = CHILDID_SELF;
+    } else { // its not create an Accessible for it.
+      pvarChild->vt = VT_DISPATCH;
+      pvarChild->pdispVal = NativeAccessible(accessible);
+    }
+  } else {
+    // no child at that point
+    pvarChild->vt = VT_EMPTY;
+    return S_FALSE;
+  }
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::accDoDefaultAction(
+      /* [optional][in] */ VARIANT varChild)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  RefPtr<IAccessible> accessible;
+  HRESULT hr = ResolveChild(varChild, getter_AddRefs(accessible));
+  if (FAILED(hr)) {
+    return hr;
+  }
+
+  if (accessible) {
+    return accessible->accDoDefaultAction(kVarChildIdSelf);
+  }
+
+  return DoAction(0) ? S_OK : E_INVALIDARG;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+AccessibleWrap::put_accName(
+      /* [optional][in] */ VARIANT varChild,
+      /* [in] */ BSTR szName)
+{
+  return E_NOTIMPL;
+}
+
+STDMETHODIMP
+AccessibleWrap::put_accValue(
+      /* [optional][in] */ VARIANT varChild,
+      /* [in] */ BSTR szValue)
+{
+  return E_NOTIMPL;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// IDispatch
+
+STDMETHODIMP
+AccessibleWrap::GetTypeInfoCount(UINT *pctinfo)
+{
+  if (!pctinfo)
+    return E_INVALIDARG;
+
+  *pctinfo = 1;
+  return S_OK;
+}
+
+STDMETHODIMP
+AccessibleWrap::GetTypeInfo(UINT iTInfo, LCID lcid, ITypeInfo **ppTInfo)
+{
+  if (!ppTInfo)
+    return E_INVALIDARG;
+
+  *ppTInfo = nullptr;
+
+  if (iTInfo != 0)
+    return DISP_E_BADINDEX;
+
+  ITypeInfo * typeInfo = GetTI(lcid);
+  if (!typeInfo)
+    return E_FAIL;
+
+  typeInfo->AddRef();
+  *ppTInfo = typeInfo;
+
+  return S_OK;
+}
+
+STDMETHODIMP
+AccessibleWrap::GetIDsOfNames(REFIID riid, LPOLESTR *rgszNames,
+                              UINT cNames, LCID lcid, DISPID *rgDispId)
+{
+  ITypeInfo *typeInfo = GetTI(lcid);
+  if (!typeInfo)
+    return E_FAIL;
+
+  HRESULT hr = DispGetIDsOfNames(typeInfo, rgszNames, cNames, rgDispId);
+  return hr;
+}
+
+STDMETHODIMP
+AccessibleWrap::Invoke(DISPID dispIdMember, REFIID riid,
+                       LCID lcid, WORD wFlags, DISPPARAMS *pDispParams,
+                       VARIANT *pVarResult, EXCEPINFO *pExcepInfo,
+                       UINT *puArgErr)
+{
+  ITypeInfo *typeInfo = GetTI(lcid);
+  if (!typeInfo)
+    return E_FAIL;
+
+  return typeInfo->Invoke(static_cast<IAccessible*>(this), dispIdMember,
+                          wFlags, pDispParams, pVarResult, pExcepInfo,
+                          puArgErr);
+}
+
+void
+AccessibleWrap::GetNativeInterface(void** aOutAccessible)
+{
+  *aOutAccessible = static_cast<IAccessible*>(this);
+  NS_ADDREF_THIS();
+}
+
+void
+AccessibleWrap::SetID(uint32_t aID)
+{
+  MOZ_ASSERT(XRE_IsParentProcess() && IsProxy());
+  mID = aID;
+}
+
+void
+AccessibleWrap::FireWinEvent(Accessible* aTarget, uint32_t aEventType)
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+  static_assert(sizeof(gWinEventMap)/sizeof(gWinEventMap[0]) == nsIAccessibleEvent::EVENT_LAST_ENTRY,
+                "MSAA event map skewed");
+
+  NS_ASSERTION(aEventType > 0 && aEventType < ArrayLength(gWinEventMap), "invalid event type");
+
+  uint32_t winEvent = gWinEventMap[aEventType];
+  if (!winEvent)
+    return;
+
+  int32_t childID = GetChildIDFor(aTarget);
+  if (!childID)
+    return; // Can't fire an event without a child ID
+
+  HWND hwnd = GetHWNDFor(aTarget);
+  if (!hwnd) {
+    return;
+  }
+
+  // Fire MSAA event for client area window.
+  ::NotifyWinEvent(winEvent, hwnd, OBJID_CLIENT, childID);
+
+  // JAWS announces collapsed combobox navigation based on focus events.
+  if (aEventType == nsIAccessibleEvent::EVENT_SELECTION &&
+      Compatibility::IsJAWS()) {
+    roles::Role role = aTarget->IsProxy() ? aTarget->Proxy()->Role() :
+      aTarget->Role();
+    if (role == roles::COMBOBOX_OPTION) {
+      ::NotifyWinEvent(EVENT_OBJECT_FOCUS, hwnd, OBJID_CLIENT, childID);
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Accessible
+
+nsresult
+AccessibleWrap::HandleAccEvent(AccEvent* aEvent)
+{
+  nsresult rv = Accessible::HandleAccEvent(aEvent);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  if (IPCAccessibilityActive()) {
+    return NS_OK;
+  }
+
+  uint32_t eventType = aEvent->GetEventType();
+
+  // Means we're not active.
+  NS_ENSURE_TRUE(!IsDefunct(), NS_ERROR_FAILURE);
+
+  Accessible* accessible = aEvent->GetAccessible();
+  if (!accessible)
+    return NS_OK;
+
+  if (eventType == nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED ||
+      eventType == nsIAccessibleEvent::EVENT_FOCUS) {
+    UpdateSystemCaretFor(accessible);
+  }
+
+  FireWinEvent(accessible, eventType);
+
+  return NS_OK;
+}
+
+DocProxyAccessibleWrap*
+AccessibleWrap::DocProxyWrapper() const
+{
+  MOZ_ASSERT(IsProxy());
+
+  ProxyAccessible* proxy = Proxy();
+  if (!proxy) {
+    return nullptr;
+  }
+
+  AccessibleWrap* acc = WrapperFor(proxy->Document());
+  MOZ_ASSERT(acc->IsDoc());
+
+ return static_cast<DocProxyAccessibleWrap*>(acc);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// AccessibleWrap
+
+//------- Helper methods ---------
+
+int32_t
+AccessibleWrap::GetChildIDFor(Accessible* aAccessible)
+{
+  // A child ID of the window is required, when we use NotifyWinEvent,
+  // so that the 3rd party application can call back and get the IAccessible
+  // the event occurred on.
+
+  if (!aAccessible) {
+    return 0;
+  }
+
+  // Chrome should use mID which has been generated by the content process.
+  if (aAccessible->IsProxy()) {
+    const uint32_t id = static_cast<AccessibleWrap*>(aAccessible)->mID;
+    MOZ_ASSERT(id != kNoID);
+    return id;
+  }
+
+  if (!aAccessible->Document())
+    return 0;
+
+  uint32_t* id = & static_cast<AccessibleWrap*>(aAccessible)->mID;
+  if (*id != kNoID)
+    return *id;
+
+  *id = sIDGen.GetID();
+
+  MOZ_ASSERT(!aAccessible->IsProxy());
+  DocAccessibleWrap* doc =
+    static_cast<DocAccessibleWrap*>(aAccessible->Document());
+  doc->AddID(*id, static_cast<AccessibleWrap*>(aAccessible));
+
+  return *id;
+}
+
+HWND
+AccessibleWrap::GetHWNDFor(Accessible* aAccessible)
+{
+  if (!aAccessible) {
+    return nullptr;
+  }
+
+  if (XRE_IsContentProcess()) {
+    DocAccessible* doc = aAccessible->Document();
+    if (!doc) {
+      return nullptr;
+    }
+
+    DocAccessibleChild* ipcDoc = doc->IPCDoc();
+    if (!ipcDoc) {
+      return nullptr;
+    }
+
+    auto tab = static_cast<dom::TabChild*>(ipcDoc->Manager());
+    MOZ_ASSERT(tab);
+    return reinterpret_cast<HWND>(tab->GetNativeWindowHandle());
+  }
+
+  // Accessibles in child processes are said to have the HWND of the window
+  // their tab is within.  Popups are always in the parent process, and so
+  // never proxied, which means this is basically correct.
+  if (aAccessible->IsProxy()) {
+    ProxyAccessible* proxy = aAccessible->Proxy();
+    if (!proxy) {
+      return nullptr;
+    }
+
+    Accessible* outerDoc = proxy->OuterDocOfRemoteBrowser();
+    NS_ASSERTION(outerDoc, "no outer doc for accessible remote tab!");
+    if (!outerDoc) {
+      return nullptr;
+    }
+
+    return GetHWNDFor(outerDoc);
+  }
+
+  DocAccessible* document = aAccessible->Document();
+  if(!document)
+    return nullptr;
+
+  // Popup lives in own windows, use its HWND until the popup window is
+  // hidden to make old JAWS versions work with collapsed comboboxes (see
+  // discussion in bug 379678).
+  nsIFrame* frame = aAccessible->GetFrame();
+  if (frame) {
+    nsIWidget* widget = frame->GetNearestWidget();
+    if (widget && widget->IsVisible()) {
+      nsIPresShell* shell = document->PresShell();
+      nsViewManager* vm = shell->GetViewManager();
+      if (vm) {
+        nsCOMPtr<nsIWidget> rootWidget;
+        vm->GetRootWidget(getter_AddRefs(rootWidget));
+        // Make sure the accessible belongs to popup. If not then use
+        // document HWND (which might be different from root widget in the
+        // case of window emulation).
+        if (rootWidget != widget)
+          return static_cast<HWND>(widget->GetNativeData(NS_NATIVE_WINDOW));
+      }
+    }
+  }
+
+  return static_cast<HWND>(document->GetNativeWindow());
+}
+
+IDispatch*
+AccessibleWrap::NativeAccessible(Accessible* aAccessible)
+{
+  if (!aAccessible) {
+    NS_WARNING("Not passing in an aAccessible");
+    return nullptr;
+  }
+
+  IAccessible* msaaAccessible = nullptr;
+  aAccessible->GetNativeInterface(reinterpret_cast<void**>(&msaaAccessible));
+  return static_cast<IDispatch*>(msaaAccessible);
+}
+
+static Accessible*
+GetAccessibleInSubtree(DocAccessible* aDoc, uint32_t aID)
+{
+  Accessible* child = static_cast<DocAccessibleWrap*>(aDoc)->GetAccessibleByID(aID);
+  if (child)
+    return child;
+
+  uint32_t childDocCount = aDoc->ChildDocumentCount();
+  for (uint32_t i = 0; i < childDocCount; i++) {
+    child = GetAccessibleInSubtree(aDoc->GetChildDocumentAt(i), aID);
+    if (child)
+      return child;
+  }
+
+    return nullptr;
+  }
+
+static already_AddRefed<IDispatch>
+GetProxiedAccessibleInSubtree(const DocAccessibleParent* aDoc,
+                              const VARIANT& aVarChild)
+{
+  auto wrapper = static_cast<DocProxyAccessibleWrap*>(WrapperFor(aDoc));
+  RefPtr<IAccessible> comProxy;
+  int32_t wrapperChildId = AccessibleWrap::GetChildIDFor(wrapper);
+  if (wrapperChildId == aVarChild.lVal) {
+    wrapper->GetNativeInterface(getter_AddRefs(comProxy));
+    return comProxy.forget();
+  }
+
+  MOZ_ASSERT(aDoc->IsTopLevel());
+  if (!aDoc->IsTopLevel()) {
+    return nullptr;
+  }
+
+  wrapper->GetNativeInterface(getter_AddRefs(comProxy));
+  MOZ_ASSERT(comProxy);
+  if (!comProxy) {
+    return nullptr;
+  }
+
+  RefPtr<IDispatch> disp;
+  if (FAILED(comProxy->get_accChild(aVarChild, getter_AddRefs(disp)))) {
+    return nullptr;
+  }
+
+  return disp.forget();
+}
+
+already_AddRefed<IAccessible>
+AccessibleWrap::GetIAccessibleFor(const VARIANT& aVarChild, bool* aIsDefunct)
+{
+  if (aVarChild.vt != VT_I4)
+    return nullptr;
+
+  VARIANT varChild = aVarChild;
+
+  MOZ_ASSERT(aIsDefunct);
+  *aIsDefunct = false;
+
+  RefPtr<IAccessible> result;
+
+  if (varChild.lVal == CHILDID_SELF) {
+    *aIsDefunct = IsDefunct();
+    if (*aIsDefunct) {
+      return nullptr;
+    }
+    GetNativeInterface(getter_AddRefs(result));
+    if (result) {
+      return result.forget();
+    }
+    // If we're not a proxy, there's nothing more we can do to attempt to
+    // resolve the IAccessible, so we just fail.
+    if (!IsProxy()) {
+      return nullptr;
+    }
+    // Otherwise, since we're a proxy and we have a null native interface, this
+    // indicates that we need to obtain a COM proxy. To do this, we'll replace
+    // CHILDID_SELF with our real MSAA ID and continue the search from there.
+    varChild.lVal = GetExistingID();
+  }
+
+  if (IsProxy() ? Proxy()->MustPruneChildren() : nsAccUtils::MustPrune(this)) {
+    return nullptr;
+  }
+
+  // If the MSAA ID is not a chrome id then we already know that we won't
+  // find it here and should look remotely instead.
+  if (XRE_IsParentProcess() && !sIDGen.IsChromeID(varChild.lVal)) {
+    return GetRemoteIAccessibleFor(varChild);
+  }
+  MOZ_ASSERT(XRE_IsParentProcess() ||
+             sIDGen.IsIDForThisContentProcess(varChild.lVal));
+
+  if (varChild.lVal > 0) {
+    // Gecko child indices are 0-based in contrast to indices used in MSAA.
+    MOZ_ASSERT(!IsProxy());
+    Accessible* xpAcc = GetChildAt(varChild.lVal - 1);
+    if (!xpAcc) {
+      return nullptr;
+    }
+    *aIsDefunct = xpAcc->IsDefunct();
+    static_cast<AccessibleWrap*>(xpAcc)->GetNativeInterface(getter_AddRefs(result));
+    return result.forget();
+  }
+
+  // If lVal negative then it is treated as child ID and we should look for
+  // accessible through whole accessible subtree including subdocuments.
+  // Otherwise we treat lVal as index in parent.
+  // First handle the case that both this accessible and the id'd one are in
+  // this process.
+  if (!IsProxy()) {
+    DocAccessible* document = Document();
+    Accessible* child =
+      GetAccessibleInSubtree(document, static_cast<uint32_t>(varChild.lVal));
+
+    // If it is a document then just return an accessible.
+    if (child && IsDoc()) {
+      *aIsDefunct = child->IsDefunct();
+      static_cast<AccessibleWrap*>(child)->GetNativeInterface(getter_AddRefs(result));
+      return result.forget();
+    }
+
+    // Otherwise check whether the accessible is a child (this path works for
+    // ARIA documents and popups).
+    Accessible* parent = child;
+    while (parent && parent != document) {
+      if (parent == this) {
+        *aIsDefunct = child->IsDefunct();
+        static_cast<AccessibleWrap*>(child)->GetNativeInterface(getter_AddRefs(result));
+        return result.forget();
+      }
+
+      parent = parent->Parent();
+    }
+  }
+
+  // Now see about the case that both this accessible and the target one are
+  // proxied.
+  if (IsProxy()) {
+    DocAccessibleParent* proxyDoc = Proxy()->Document();
+    RefPtr<IDispatch> disp = GetProxiedAccessibleInSubtree(proxyDoc, varChild);
+    if (!disp) {
+      return nullptr;
+    }
+
+    MOZ_ASSERT(mscom::IsProxy(disp));
+    DebugOnly<HRESULT> hr = disp->QueryInterface(IID_IAccessible,
+                                                 getter_AddRefs(result));
+    MOZ_ASSERT(SUCCEEDED(hr));
+    return result.forget();
+  }
+
+  return nullptr;
+}
+
+already_AddRefed<IAccessible>
+AccessibleWrap::GetRemoteIAccessibleFor(const VARIANT& aVarChild)
+{
+  DocAccessibleParent* proxyDoc = nullptr;
+  DocAccessible* doc = Document();
+  const nsTArray<DocAccessibleParent*>* remoteDocs =
+    DocManager::TopLevelRemoteDocs();
+  if (!remoteDocs) {
+    return nullptr;
+  }
+
+  RefPtr<IAccessible> result;
+
+  size_t docCount = remoteDocs->Length();
+  for (size_t i = 0; i < docCount; i++) {
+    DocAccessibleParent* remoteDoc = remoteDocs->ElementAt(i);
+
+    uint32_t remoteDocMsaaId = WrapperFor(remoteDoc)->GetExistingID();
+    if (!sIDGen.IsSameContentProcessFor(aVarChild.lVal, remoteDocMsaaId)) {
+      continue;
+    }
+
+    Accessible* outerDoc = remoteDoc->OuterDocOfRemoteBrowser();
+    if (!outerDoc) {
+      continue;
+    }
+
+    if (outerDoc->Document() != doc) {
+      continue;
+    }
+
+    RefPtr<IDispatch> disp =
+      GetProxiedAccessibleInSubtree(remoteDoc, aVarChild);
+    if (!disp) {
+      continue;
+    }
+
+    DebugOnly<HRESULT> hr = disp->QueryInterface(IID_IAccessible,
+                                                 getter_AddRefs(result));
+    MOZ_ASSERT(SUCCEEDED(hr));
+    return result.forget();
+  }
+
+  return nullptr;
+}
+
+void
+AccessibleWrap::UpdateSystemCaretFor(Accessible* aAccessible)
+{
+  // Move the system caret so that Windows Tablet Edition and tradional ATs with 
+  // off-screen model can follow the caret
+  ::DestroyCaret();
+
+  HyperTextAccessible* text = aAccessible->AsHyperText();
+  if (!text)
+    return;
+
+  nsIWidget* widget = nullptr;
+  LayoutDeviceIntRect caretRect = text->GetCaretRect(&widget);
+  HWND caretWnd;
+  if (caretRect.IsEmpty() || !(caretWnd = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW))) {
+    return;
+  }
+
+  // Create invisible bitmap for caret, otherwise its appearance interferes
+  // with Gecko caret
+  HBITMAP caretBitMap = CreateBitmap(1, caretRect.height, 1, 1, nullptr);
+  if (::CreateCaret(caretWnd, caretBitMap, 1, caretRect.height)) {  // Also destroys the last caret
+    ::ShowCaret(caretWnd);
+    RECT windowRect;
+    ::GetWindowRect(caretWnd, &windowRect);
+    ::SetCaretPos(caretRect.x - windowRect.left, caretRect.y - windowRect.top);
+    ::DeleteObject(caretBitMap);
+  }
+}
+
+ITypeInfo*
+AccessibleWrap::GetTI(LCID lcid)
+{
+  if (gTypeInfo)
+    return gTypeInfo;
+
+  ITypeLib *typeLib = nullptr;
+  HRESULT hr = LoadRegTypeLib(LIBID_Accessibility, 1, 0, lcid, &typeLib);
+  if (FAILED(hr))
+    return nullptr;
+
+  hr = typeLib->GetTypeInfoOfGuid(IID_IAccessible, &gTypeInfo);
+  typeLib->Release();
+
+  if (FAILED(hr))
+    return nullptr;
+
+  return gTypeInfo;
+}
+
+/* static */
+uint32_t
+AccessibleWrap::GetContentProcessIdFor(dom::ContentParentId aIPCContentId)
+{
+  return sIDGen.GetContentProcessIDFor(aIPCContentId);
+}
+
+/* static */
+void
+AccessibleWrap::ReleaseContentProcessIdFor(dom::ContentParentId aIPCContentId)
+{
+  sIDGen.ReleaseContentProcessIDFor(aIPCContentId);
+}
diff --git a/accessible/windows/msaa/AccessibleWrap.h b/accessible/windows/msaa/AccessibleWrap.h
new file mode 100644
index 000000000..eb97c2667
--- /dev/null
+++ b/accessible/windows/msaa/AccessibleWrap.h
@@ -0,0 +1,265 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_AccessibleWrap_h_
+#define mozilla_a11y_AccessibleWrap_h_
+
+#include "nsCOMPtr.h"
+#include "Accessible.h"
+#include "Accessible2.h"
+#include "ia2Accessible.h"
+#include "ia2AccessibleComponent.h"
+#include "ia2AccessibleHyperlink.h"
+#include "ia2AccessibleValue.h"
+#include "mozilla/a11y/MsaaIdGenerator.h"
+#include "mozilla/a11y/ProxyAccessible.h"
+#include "mozilla/Attributes.h"
+
+#ifdef __GNUC__
+// Inheriting from both XPCOM and MSCOM interfaces causes a lot of warnings
+// about virtual functions being hidden by each other. This is done by
+// design, so silence the warning.
+#pragma GCC diagnostic ignored "-Woverloaded-virtual"
+#endif
+
+namespace mozilla {
+namespace a11y {
+class DocProxyAccessibleWrap;
+
+class AccessibleWrap : public Accessible,
+                       public ia2Accessible,
+                       public ia2AccessibleComponent,
+                       public ia2AccessibleHyperlink,
+                       public ia2AccessibleValue
+{
+public: // construction, destruction
+  AccessibleWrap(nsIContent* aContent, DocAccessible* aDoc);
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  public: // IUnknown methods - see iunknown.h for documentation
+    STDMETHODIMP QueryInterface(REFIID, void**) override;
+
+  // Return the registered OLE class ID of this object's CfDataObj.
+    CLSID GetClassID() const;
+
+  public: // COM interface IAccessible
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accParent( 
+        /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispParent) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accChildCount( 
+        /* [retval][out] */ long __RPC_FAR *pcountChildren) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accChild( 
+        /* [in] */ VARIANT varChild,
+        /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispChild) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accName( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszName) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accValue( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszValue) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accDescription( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszDescription) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accRole( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarRole) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accState( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarState) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accHelp( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszHelp) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accHelpTopic( 
+        /* [out] */ BSTR __RPC_FAR *pszHelpFile,
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ long __RPC_FAR *pidTopic) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accKeyboardShortcut( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszKeyboardShortcut) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accFocus( 
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarChild) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accSelection( 
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarChildren) override;
+
+    virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accDefaultAction( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [retval][out] */ BSTR __RPC_FAR *pszDefaultAction) override;
+
+    virtual /* [id] */ HRESULT STDMETHODCALLTYPE accSelect( 
+        /* [in] */ long flagsSelect,
+        /* [optional][in] */ VARIANT varChild) override;
+
+    virtual /* [id] */ HRESULT STDMETHODCALLTYPE accLocation( 
+        /* [out] */ long __RPC_FAR *pxLeft,
+        /* [out] */ long __RPC_FAR *pyTop,
+        /* [out] */ long __RPC_FAR *pcxWidth,
+        /* [out] */ long __RPC_FAR *pcyHeight,
+        /* [optional][in] */ VARIANT varChild) override;
+
+    virtual /* [id] */ HRESULT STDMETHODCALLTYPE accNavigate( 
+        /* [in] */ long navDir,
+        /* [optional][in] */ VARIANT varStart,
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarEndUpAt) override;
+
+    virtual /* [id] */ HRESULT STDMETHODCALLTYPE accHitTest( 
+        /* [in] */ long xLeft,
+        /* [in] */ long yTop,
+        /* [retval][out] */ VARIANT __RPC_FAR *pvarChild) override;
+
+    virtual /* [id] */ HRESULT STDMETHODCALLTYPE accDoDefaultAction( 
+        /* [optional][in] */ VARIANT varChild) override;
+
+    virtual /* [id][propput] */ HRESULT STDMETHODCALLTYPE put_accName( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [in] */ BSTR szName) override;
+
+    virtual /* [id][propput] */ HRESULT STDMETHODCALLTYPE put_accValue( 
+        /* [optional][in] */ VARIANT varChild,
+        /* [in] */ BSTR szValue) override;
+
+  // IDispatch (support of scripting languages like VB)
+  virtual HRESULT STDMETHODCALLTYPE GetTypeInfoCount(UINT *pctinfo) override;
+
+  virtual HRESULT STDMETHODCALLTYPE GetTypeInfo(UINT iTInfo, LCID lcid,
+                                                ITypeInfo **ppTInfo) override;
+
+  virtual HRESULT STDMETHODCALLTYPE GetIDsOfNames(REFIID riid,
+                                                  LPOLESTR *rgszNames,
+                                                  UINT cNames,
+                                                  LCID lcid,
+                                                  DISPID *rgDispId) override;
+
+  virtual HRESULT STDMETHODCALLTYPE Invoke(DISPID dispIdMember, REFIID riid,
+                                           LCID lcid, WORD wFlags,
+                                           DISPPARAMS *pDispParams,
+                                           VARIANT *pVarResult,
+                                           EXCEPINFO *pExcepInfo,
+                                           UINT *puArgErr) override;
+
+  // Accessible
+  virtual nsresult HandleAccEvent(AccEvent* aEvent) override;
+  virtual void Shutdown() override;
+
+  // Helper methods
+  static int32_t GetChildIDFor(Accessible* aAccessible);
+  static HWND GetHWNDFor(Accessible* aAccessible);
+
+  static void FireWinEvent(Accessible* aTarget, uint32_t aEventType);
+
+  /**
+   * System caret support: update the Windows caret position. 
+   * The system caret works more universally than the MSAA caret
+   * For example, Window-Eyes, JAWS, ZoomText and Windows Tablet Edition use it
+   * We will use an invisible system caret.
+   * Gecko is still responsible for drawing its own caret
+   */
+  void UpdateSystemCaretFor(Accessible* aAccessible);
+
+  /**
+   * Find an accessible by the given child ID in cached documents.
+   */
+  MOZ_MUST_USE already_AddRefed<IAccessible>
+  GetIAccessibleFor(const VARIANT& aVarChild, bool* aIsDefunct);
+
+  virtual void GetNativeInterface(void **aOutAccessible) override;
+
+  static IDispatch* NativeAccessible(Accessible* aAccessible);
+
+  uint32_t GetExistingID() const { return mID; }
+  static const uint32_t kNoID = 0;
+  void SetID(uint32_t aID);
+
+  static uint32_t GetContentProcessIdFor(dom::ContentParentId aIPCContentId);
+  static void ReleaseContentProcessIdFor(dom::ContentParentId aIPCContentId);
+
+protected:
+  virtual ~AccessibleWrap();
+
+  uint32_t mID;
+
+  HRESULT
+  ResolveChild(const VARIANT& aVarChild, IAccessible** aOutInterface);
+
+  /**
+   * Find a remote accessible by the given child ID.
+   */
+  MOZ_MUST_USE already_AddRefed<IAccessible>
+  GetRemoteIAccessibleFor(const VARIANT& aVarChild);
+
+  /**
+   * Return the wrapper for the document's proxy.
+   */
+  DocProxyAccessibleWrap* DocProxyWrapper() const;
+
+  /**
+   * Creates ITypeInfo for LIBID_Accessibility if it's needed and returns it.
+   */
+  static ITypeInfo* GetTI(LCID lcid);
+
+  static ITypeInfo* gTypeInfo;
+
+  static MsaaIdGenerator sIDGen;
+
+  enum navRelations {
+    NAVRELATION_CONTROLLED_BY = 0x1000,
+    NAVRELATION_CONTROLLER_FOR = 0x1001,
+    NAVRELATION_LABEL_FOR = 0x1002,
+    NAVRELATION_LABELLED_BY = 0x1003,
+    NAVRELATION_MEMBER_OF = 0x1004,
+    NAVRELATION_NODE_CHILD_OF = 0x1005,
+    NAVRELATION_FLOWS_TO = 0x1006,
+    NAVRELATION_FLOWS_FROM = 0x1007,
+    NAVRELATION_SUBWINDOW_OF = 0x1008,
+    NAVRELATION_EMBEDS = 0x1009,
+    NAVRELATION_EMBEDDED_BY = 0x100a,
+    NAVRELATION_POPUP_FOR = 0x100b,
+    NAVRELATION_PARENT_WINDOW_OF = 0x100c,
+    NAVRELATION_DEFAULT_BUTTON = 0x100d,
+    NAVRELATION_DESCRIBED_BY = 0x100e,
+    NAVRELATION_DESCRIPTION_FOR = 0x100f,
+    NAVRELATION_NODE_PARENT_OF = 0x1010,
+    NAVRELATION_CONTAINING_DOCUMENT = 0x1011,
+    NAVRELATION_CONTAINING_TAB_PANE = 0x1012,
+    NAVRELATION_CONTAINING_APPLICATION = 0x1014,
+    NAVRELATION_DETAILS = 0x1015,
+    NAVRELATION_DETAILS_FOR = 0x1016,
+    NAVRELATION_ERROR = 0x1017,
+    NAVRELATION_ERROR_FOR = 0x1018
+  };
+};
+
+static inline AccessibleWrap*
+WrapperFor(const ProxyAccessible* aProxy)
+{
+  return reinterpret_cast<AccessibleWrap*>(aProxy->GetWrapper());
+}
+
+} // namespace a11y
+} // namespace mozilla
+
+#ifdef XP_WIN
+// Undo the windows.h damage
+#undef GetMessage
+#undef CreateEvent
+#undef GetClassName
+#undef GetBinaryType
+#undef RemoveDirectory
+#endif
+
+#endif
diff --git a/accessible/windows/msaa/ApplicationAccessibleWrap.cpp b/accessible/windows/msaa/ApplicationAccessibleWrap.cpp
new file mode 100644
index 000000000..b78a8dd55
--- /dev/null
+++ b/accessible/windows/msaa/ApplicationAccessibleWrap.cpp
@@ -0,0 +1,162 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ApplicationAccessibleWrap.h"
+
+#include "AccessibleApplication_i.c"
+#include "IUnknownImpl.h"
+
+#include "nsIGfxInfo.h"
+#include "nsIPersistentProperties2.h"
+#include "nsServiceManagerUtils.h"
+#include "mozilla/Services.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// nsISupports
+NS_IMPL_ISUPPORTS_INHERITED0(ApplicationAccessibleWrap,
+                             ApplicationAccessible)
+
+already_AddRefed<nsIPersistentProperties>
+ApplicationAccessibleWrap::NativeAttributes()
+{
+  nsCOMPtr<nsIPersistentProperties> attributes =
+    do_CreateInstance(NS_PERSISTENTPROPERTIES_CONTRACTID);
+
+  nsCOMPtr<nsIGfxInfo> gfxInfo = services::GetGfxInfo();
+  if (gfxInfo) {
+    bool isD2DEnabled = false;
+    gfxInfo->GetD2DEnabled(&isD2DEnabled);
+    nsAutoString unused;
+    attributes->SetStringProperty(
+      NS_LITERAL_CSTRING("D2D"),
+      isD2DEnabled ? NS_LITERAL_STRING("true") : NS_LITERAL_STRING("false"),
+        unused);
+  }
+
+  return attributes.forget();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// IUnknown
+
+STDMETHODIMP
+ApplicationAccessibleWrap::QueryInterface(REFIID iid, void** ppv)
+{
+  if (!ppv)
+    return E_INVALIDARG;
+
+  *ppv = nullptr;
+
+  if (IID_IAccessibleApplication == iid) {
+    *ppv = static_cast<IAccessibleApplication*>(this);
+    (reinterpret_cast<IUnknown*>(*ppv))->AddRef();
+    return S_OK;
+  }
+
+  return AccessibleWrap::QueryInterface(iid, ppv);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// IAccessibleApplication
+
+STDMETHODIMP
+ApplicationAccessibleWrap::get_appName(BSTR* aName)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aName)
+    return E_INVALIDARG;
+
+  *aName = nullptr;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  nsAutoString name;
+  AppName(name);
+  if (name.IsEmpty())
+    return S_FALSE;
+
+  *aName = ::SysAllocStringLen(name.get(), name.Length());
+  return *aName ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ApplicationAccessibleWrap::get_appVersion(BSTR* aVersion)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aVersion)
+    return E_INVALIDARG;
+
+  *aVersion = nullptr;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  nsAutoString version;
+  AppVersion(version);
+  if (version.IsEmpty())
+    return S_FALSE;
+
+  *aVersion = ::SysAllocStringLen(version.get(), version.Length());
+  return *aVersion ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ApplicationAccessibleWrap::get_toolkitName(BSTR* aName)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aName)
+    return E_INVALIDARG;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  nsAutoString name;
+  PlatformName(name);
+  if (name.IsEmpty())
+    return S_FALSE;
+
+  *aName = ::SysAllocStringLen(name.get(), name.Length());
+  return *aName ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ApplicationAccessibleWrap::get_toolkitVersion(BSTR* aVersion)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aVersion)
+    return E_INVALIDARG;
+
+  *aVersion = nullptr;
+
+  if (IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  nsAutoString version;
+  PlatformVersion(version);
+  if (version.IsEmpty())
+    return S_FALSE;
+
+  *aVersion = ::SysAllocStringLen(version.get(), version.Length());
+  return *aVersion ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
diff --git a/accessible/windows/msaa/ApplicationAccessibleWrap.h b/accessible/windows/msaa/ApplicationAccessibleWrap.h
new file mode 100644
index 000000000..a427e98f5
--- /dev/null
+++ b/accessible/windows/msaa/ApplicationAccessibleWrap.h
@@ -0,0 +1,52 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_ApplicationAccessibleWrap_h__
+#define mozilla_a11y_ApplicationAccessibleWrap_h__
+
+#include "ApplicationAccessible.h"
+
+#include "AccessibleApplication.h"
+
+namespace mozilla {
+namespace a11y {
+ 
+class ApplicationAccessibleWrap: public ApplicationAccessible,
+                                 public IAccessibleApplication
+{
+  ~ApplicationAccessibleWrap() {}
+
+public:
+  // nsISupporst
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // nsAccessible
+  virtual already_AddRefed<nsIPersistentProperties> NativeAttributes() override;
+
+  // IUnknown
+  STDMETHODIMP QueryInterface(REFIID, void**);
+
+  // IAccessibleApplication
+  virtual /* [propget] */ HRESULT STDMETHODCALLTYPE get_appName(
+            /* [retval][out] */ BSTR *name);
+
+  virtual /* [propget] */ HRESULT STDMETHODCALLTYPE get_appVersion(
+      /* [retval][out] */ BSTR *version);
+
+  virtual /* [propget] */ HRESULT STDMETHODCALLTYPE get_toolkitName(
+      /* [retval][out] */ BSTR *name);
+
+  virtual /* [propget] */ HRESULT STDMETHODCALLTYPE get_toolkitVersion(
+          /* [retval][out] */ BSTR *version);
+
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
+
diff --git a/accessible/windows/msaa/Compatibility.cpp b/accessible/windows/msaa/Compatibility.cpp
new file mode 100644
index 000000000..31026c586
--- /dev/null
+++ b/accessible/windows/msaa/Compatibility.cpp
@@ -0,0 +1,112 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Compatibility.h"
+
+#include "nsWinUtils.h"
+#include "Statistics.h"
+
+#include "mozilla/Preferences.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+/**
+ * Return true if module version is lesser than the given version.
+ */
+bool
+IsModuleVersionLessThan(HMODULE aModuleHandle, DWORD aMajor, DWORD aMinor)
+{
+  wchar_t fileName[MAX_PATH];
+  ::GetModuleFileNameW(aModuleHandle, fileName, MAX_PATH);
+
+  DWORD dummy = 0;
+  DWORD length = ::GetFileVersionInfoSizeW(fileName, &dummy);
+
+  LPBYTE versionInfo = new BYTE[length];
+  ::GetFileVersionInfoW(fileName, 0, length, versionInfo);
+
+  UINT uLen;
+  VS_FIXEDFILEINFO* fixedFileInfo = nullptr;
+  ::VerQueryValueW(versionInfo, L"\\", (LPVOID*)&fixedFileInfo, &uLen);
+  DWORD dwFileVersionMS = fixedFileInfo->dwFileVersionMS;
+  DWORD dwFileVersionLS = fixedFileInfo->dwFileVersionLS;
+  delete [] versionInfo;
+
+  DWORD dwLeftMost = HIWORD(dwFileVersionMS);
+  DWORD dwSecondRight = HIWORD(dwFileVersionLS);
+  return (dwLeftMost < aMajor ||
+    (dwLeftMost == aMajor && dwSecondRight < aMinor));
+}
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Compatibility
+////////////////////////////////////////////////////////////////////////////////
+
+uint32_t Compatibility::sConsumers = Compatibility::UNKNOWN;
+
+void
+Compatibility::Init()
+{
+  // Note we collect some AT statistics/telemetry here for convenience.
+
+  HMODULE jawsHandle = ::GetModuleHandleW(L"jhook");
+  if (jawsHandle)
+    sConsumers |= (IsModuleVersionLessThan(jawsHandle, 8, 2173)) ?
+                   OLDJAWS : JAWS;
+
+  if (::GetModuleHandleW(L"gwm32inc"))
+    sConsumers |= WE;
+
+  if (::GetModuleHandleW(L"dolwinhk"))
+    sConsumers |= DOLPHIN;
+
+  if (::GetModuleHandleW(L"STSA32"))
+    sConsumers |= SEROTEK;
+
+  if (::GetModuleHandleW(L"nvdaHelperRemote"))
+    sConsumers |= NVDA;
+
+  if (::GetModuleHandleW(L"OsmHooks"))
+    sConsumers |= COBRA;
+
+  if (::GetModuleHandleW(L"WebFinderRemote"))
+    sConsumers |= ZOOMTEXT;
+
+  if (::GetModuleHandleW(L"Kazahook"))
+    sConsumers |= KAZAGURU;
+
+  if (::GetModuleHandleW(L"TextExtractorImpl32") ||
+      ::GetModuleHandleW(L"TextExtractorImpl64"))
+    sConsumers |= YOUDAO;
+
+  if (::GetModuleHandleW(L"uiautomation") ||
+      ::GetModuleHandleW(L"uiautomationcore"))
+    sConsumers |= UIAUTOMATION;
+
+  // If we have a known consumer remove the unknown bit.
+  if (sConsumers != Compatibility::UNKNOWN)
+    sConsumers ^= Compatibility::UNKNOWN;
+
+  // Gather telemetry
+  uint32_t temp = sConsumers;
+  for (int i = 0; temp; i++) {
+    if (temp & 0x1)
+      statistics::A11yConsumers(i);
+
+    temp >>= 1;
+  }
+
+  // Turn off new tab switching for Jaws and WE.
+  if (sConsumers & (JAWS | OLDJAWS | WE)) {
+    // Check to see if the pref for disallowing CtrlTab is already set. If so,
+    // bail out (respect the user settings). If not, set it.
+    if (!Preferences::HasUserValue("browser.ctrlTab.disallowForScreenReaders"))
+      Preferences::SetBool("browser.ctrlTab.disallowForScreenReaders", true);
+  }
+}
+
diff --git a/accessible/windows/msaa/Compatibility.h b/accessible/windows/msaa/Compatibility.h
new file mode 100644
index 000000000..dd9a82f7c
--- /dev/null
+++ b/accessible/windows/msaa/Compatibility.h
@@ -0,0 +1,79 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef COMPATIBILITY_MANAGER_H
+#define COMPATIBILITY_MANAGER_H
+
+#include <stdint.h>
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * Used to get compatibility modes. Note, modes are computed at accessibility
+ * start up time and aren't changed during lifetime.
+ */
+class Compatibility
+{
+public:
+  /**
+   * Return true if IAccessible2 disabled.
+   */
+  static bool IsIA2Off() { return !!(sConsumers & OLDJAWS); }
+
+  /**
+   * Return true if JAWS mode is enabled.
+   */
+  static bool IsJAWS() { return !!(sConsumers & (JAWS | OLDJAWS)); }
+
+  /**
+   * Return true if WE mode is enabled.
+   */
+  static bool IsWE() { return !!(sConsumers & WE); }
+
+  /**
+   * Return true if Dolphin mode is enabled.
+   */
+  static bool IsDolphin() { return !!(sConsumers & DOLPHIN); }
+
+private:
+  Compatibility();
+  Compatibility(const Compatibility&);
+  Compatibility& operator = (const Compatibility&);
+
+  /**
+   * Initialize compatibility mode. Called by platform (see Platform.h) during
+   * accessibility initialization.
+   */
+  static void Init();
+  friend void PlatformInit();
+
+  /**
+   * List of detected consumers of a11y (used for statistics/telemetry and compat)
+   */
+  enum {
+    NVDA = 1 << 0,
+    JAWS = 1 << 1,
+    OLDJAWS = 1 << 2,
+    WE = 1 << 3,
+    DOLPHIN = 1 << 4,
+    SEROTEK = 1 << 5,
+    COBRA = 1 << 6,
+    ZOOMTEXT = 1 << 7,
+    KAZAGURU = 1 << 8,
+    YOUDAO = 1 << 9,
+    UNKNOWN = 1 << 10,
+    UIAUTOMATION = 1 << 11
+  };
+
+private:
+  static uint32_t sConsumers;
+};
+
+} // a11y namespace
+} // mozilla namespace
+
+#endif
diff --git a/accessible/windows/msaa/DocAccessibleWrap.cpp b/accessible/windows/msaa/DocAccessibleWrap.cpp
new file mode 100644
index 000000000..6fb89816d
--- /dev/null
+++ b/accessible/windows/msaa/DocAccessibleWrap.cpp
@@ -0,0 +1,165 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DocAccessibleWrap.h"
+
+#include "Compatibility.h"
+#include "DocAccessibleChild.h"
+#include "nsWinUtils.h"
+#include "Role.h"
+#include "RootAccessible.h"
+#include "sdnDocAccessible.h"
+#include "Statistics.h"
+
+#include "nsIDocShell.h"
+#include "nsIInterfaceRequestorUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// DocAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+DocAccessibleWrap::
+  DocAccessibleWrap(nsIDocument* aDocument, nsIPresShell* aPresShell) :
+  DocAccessible(aDocument, aPresShell), mHWND(nullptr)
+{
+}
+
+DocAccessibleWrap::~DocAccessibleWrap()
+{
+}
+
+IMPL_IUNKNOWN_QUERY_HEAD(DocAccessibleWrap)
+  if (aIID == IID_ISimpleDOMDocument) {
+    statistics::ISimpleDOMUsed();
+    *aInstancePtr = static_cast<ISimpleDOMDocument*>(new sdnDocAccessible(this));
+    static_cast<IUnknown*>(*aInstancePtr)->AddRef();
+    return S_OK;
+  }
+IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(HyperTextAccessibleWrap)
+
+STDMETHODIMP
+DocAccessibleWrap::get_accParent(
+      /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispParent)
+{
+  // We might be a top-level document in a content process.
+  DocAccessibleChild* ipcDoc = IPCDoc();
+  if (!ipcDoc) {
+    return DocAccessible::get_accParent(ppdispParent);
+  }
+  IAccessible* dispParent = ipcDoc->GetParentIAccessible();
+  if (!dispParent) {
+    return S_FALSE;
+  }
+
+  dispParent->AddRef();
+  *ppdispParent = static_cast<IDispatch*>(dispParent);
+  return S_OK;
+}
+
+STDMETHODIMP
+DocAccessibleWrap::get_accValue(VARIANT aVarChild, BSTR __RPC_FAR* aValue)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aValue)
+    return E_INVALIDARG;
+  *aValue = nullptr;
+
+  // For backwards-compat, we still support old MSAA hack to provide URL in accValue
+  // Check for real value first
+  HRESULT hr = AccessibleWrap::get_accValue(aVarChild, aValue);
+  if (FAILED(hr) || *aValue || aVarChild.lVal != CHILDID_SELF)
+    return hr;
+
+  // If document is being used to create a widget, don't use the URL hack
+  roles::Role role = Role();
+  if (role != roles::DOCUMENT && role != roles::APPLICATION &&
+      role != roles::DIALOG && role != roles::ALERT)
+    return hr;
+
+  nsAutoString url;
+  URL(url);
+  if (url.IsEmpty())
+    return S_FALSE;
+
+  *aValue = ::SysAllocStringLen(url.get(), url.Length());
+  return *aValue ? S_OK : E_OUTOFMEMORY;
+
+  A11Y_TRYBLOCK_END
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Accessible
+
+void
+DocAccessibleWrap::Shutdown()
+{
+  // Do window emulation specific shutdown if emulation was started.
+  if (nsWinUtils::IsWindowEmulationStarted()) {
+    // Destroy window created for root document.
+    if (mDocFlags & eTabDocument) {
+      HWND hWnd = static_cast<HWND>(mHWND);
+      ::RemovePropW(hWnd, kPropNameDocAcc);
+      ::DestroyWindow(hWnd);
+    }
+
+    mHWND = nullptr;
+  }
+
+  DocAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DocAccessible public
+
+void*
+DocAccessibleWrap::GetNativeWindow() const
+{
+  return mHWND ? mHWND : DocAccessible::GetNativeWindow();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// DocAccessible protected
+
+void
+DocAccessibleWrap::DoInitialUpdate()
+{
+  DocAccessible::DoInitialUpdate();
+
+  if (nsWinUtils::IsWindowEmulationStarted()) {
+    // Create window for tab document.
+    if (mDocFlags & eTabDocument) {
+      a11y::RootAccessible* rootDocument = RootAccessible();
+      bool isActive = true;
+      nsIntRect rect(CW_USEDEFAULT, CW_USEDEFAULT, 0, 0);
+      if (Compatibility::IsDolphin()) {
+        rect = Bounds();
+        nsIntRect rootRect = rootDocument->Bounds();
+        rect.x = rootRect.x - rect.x;
+        rect.y -= rootRect.y;
+
+        nsCOMPtr<nsISupports> container = mDocumentNode->GetContainer();
+        nsCOMPtr<nsIDocShell> docShell = do_QueryInterface(container);
+        docShell->GetIsActive(&isActive);
+      }
+
+      HWND parentWnd = reinterpret_cast<HWND>(rootDocument->GetNativeWindow());
+      mHWND = nsWinUtils::CreateNativeWindow(kClassNameTabContent, parentWnd,
+                                             rect.x, rect.y,
+                                             rect.width, rect.height, isActive);
+
+      ::SetPropW(static_cast<HWND>(mHWND), kPropNameDocAcc, (HANDLE)this);
+
+    } else {
+      DocAccessible* parentDocument = ParentDocument();
+      if (parentDocument)
+        mHWND = parentDocument->GetNativeWindow();
+    }
+  }
+}
diff --git a/accessible/windows/msaa/DocAccessibleWrap.h b/accessible/windows/msaa/DocAccessibleWrap.h
new file mode 100644
index 000000000..effa23848
--- /dev/null
+++ b/accessible/windows/msaa/DocAccessibleWrap.h
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_DocAccessibleWrap_h__
+#define mozilla_a11y_DocAccessibleWrap_h__
+
+#include "DocAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+class DocAccessibleWrap : public DocAccessible
+{
+public:
+  DocAccessibleWrap(nsIDocument* aDocument, nsIPresShell* aPresShell);
+  virtual ~DocAccessibleWrap();
+
+  DECL_IUNKNOWN_INHERITED
+
+  // IAccessible
+
+  // Override get_accParent for e10s
+  virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accParent(
+      /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispParent) override;
+
+  // Override get_accValue to provide URL when no other value is available
+  virtual /* [id][propget] */ HRESULT STDMETHODCALLTYPE get_accValue(
+      /* [optional][in] */ VARIANT varChild,
+      /* [retval][out] */ BSTR __RPC_FAR *pszValue) override;
+
+  // Accessible
+  virtual void Shutdown();
+
+  // DocAccessible
+  virtual void* GetNativeWindow() const;
+
+  /**
+   * Manage the mapping from id to Accessible.
+   */
+  void AddID(uint32_t aID, AccessibleWrap* aAcc)
+    { mIDToAccessibleMap.Put(aID, aAcc); }
+  void RemoveID(uint32_t aID) { mIDToAccessibleMap.Remove(aID); }
+  AccessibleWrap* GetAccessibleByID(uint32_t aID) const
+    { return mIDToAccessibleMap.Get(aID); }
+
+protected:
+  // DocAccessible
+  virtual void DoInitialUpdate();
+
+protected:
+  void* mHWND;
+
+  /*
+   * This provides a mapping from 32 bit id to accessible objects.
+   */
+  nsDataHashtable<nsUint32HashKey, AccessibleWrap*> mIDToAccessibleMap;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/EnumVariant.cpp b/accessible/windows/msaa/EnumVariant.cpp
new file mode 100644
index 000000000..86c81a105
--- /dev/null
+++ b/accessible/windows/msaa/EnumVariant.cpp
@@ -0,0 +1,108 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "EnumVariant.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// ChildrenEnumVariant
+////////////////////////////////////////////////////////////////////////////////
+
+IMPL_IUNKNOWN_QUERY_HEAD(ChildrenEnumVariant)
+IMPL_IUNKNOWN_QUERY_IFACE(IEnumVARIANT)
+IMPL_IUNKNOWN_QUERY_TAIL_AGGREGATED(mAnchorAcc)
+
+STDMETHODIMP
+ChildrenEnumVariant::Next(ULONG aCount, VARIANT FAR* aItems,
+                          ULONG FAR* aCountFetched)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aItems || !aCountFetched)
+    return E_INVALIDARG;
+
+  *aCountFetched = 0;
+
+  if (mAnchorAcc->IsDefunct() || mAnchorAcc->GetChildAt(mCurIndex) != mCurAcc)
+    return CO_E_OBJNOTCONNECTED;
+
+  ULONG countFetched = 0;
+  while (mCurAcc && countFetched < aCount) {
+    VariantInit(aItems + countFetched);
+
+    IDispatch* accNative = AccessibleWrap::NativeAccessible(mCurAcc);
+
+    ++mCurIndex;
+    mCurAcc = mAnchorAcc->GetChildAt(mCurIndex);
+
+    // Don't output the accessible and count it as having been fetched unless
+    // it is non-null
+    MOZ_ASSERT(accNative);
+    if (!accNative) {
+      continue;
+    }
+
+    aItems[countFetched].pdispVal = accNative;
+    aItems[countFetched].vt = VT_DISPATCH;
+    ++countFetched;
+  }
+
+  (*aCountFetched) = countFetched;
+
+  return countFetched < aCount ? S_FALSE : S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ChildrenEnumVariant::Skip(ULONG aCount)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (mAnchorAcc->IsDefunct() || mAnchorAcc->GetChildAt(mCurIndex) != mCurAcc)
+    return CO_E_OBJNOTCONNECTED;
+
+  mCurIndex += aCount;
+  mCurAcc = mAnchorAcc->GetChildAt(mCurIndex);
+
+  return mCurAcc ? S_OK : S_FALSE;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ChildrenEnumVariant::Reset()
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (mAnchorAcc->IsDefunct())
+    return CO_E_OBJNOTCONNECTED;
+
+  mCurIndex = 0;
+  mCurAcc = mAnchorAcc->GetChildAt(0);
+
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
+
+STDMETHODIMP
+ChildrenEnumVariant::Clone(IEnumVARIANT** aEnumVariant)
+{
+  A11Y_TRYBLOCK_BEGIN
+
+  if (!aEnumVariant)
+    return E_INVALIDARG;
+
+  *aEnumVariant = new ChildrenEnumVariant(*this);
+  (*aEnumVariant)->AddRef();
+
+  return S_OK;
+
+  A11Y_TRYBLOCK_END
+}
diff --git a/accessible/windows/msaa/EnumVariant.h b/accessible/windows/msaa/EnumVariant.h
new file mode 100644
index 000000000..39e342dd5
--- /dev/null
+++ b/accessible/windows/msaa/EnumVariant.h
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_EnumVariant_h__
+#define mozilla_a11y_EnumVariant_h__
+
+#include "AccessibleWrap.h"
+#include "IUnknownImpl.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * Used to fetch accessible children.
+ */
+class ChildrenEnumVariant final : public IEnumVARIANT
+{
+public:
+  ChildrenEnumVariant(AccessibleWrap* aAnchor) : mAnchorAcc(aAnchor),
+    mCurAcc(mAnchorAcc->GetChildAt(0)), mCurIndex(0) { }
+
+  // IUnknown
+  DECL_IUNKNOWN
+
+  // IEnumVariant
+  virtual /* [local] */ HRESULT STDMETHODCALLTYPE Next(
+    /* [in] */ ULONG aCount,
+    /* [length_is][size_is][out] */ VARIANT* aItems,
+    /* [out] */ ULONG* aCountFetched);
+
+  virtual HRESULT STDMETHODCALLTYPE Skip(
+    /* [in] */ ULONG aCount);
+
+  virtual HRESULT STDMETHODCALLTYPE Reset();
+
+  virtual HRESULT STDMETHODCALLTYPE Clone(
+    /* [out] */ IEnumVARIANT** aEnumVaraint);
+
+private:
+  ChildrenEnumVariant() = delete;
+  ChildrenEnumVariant& operator =(const ChildrenEnumVariant&) = delete;
+
+  ChildrenEnumVariant(const ChildrenEnumVariant& aEnumVariant) :
+    mAnchorAcc(aEnumVariant.mAnchorAcc), mCurAcc(aEnumVariant.mCurAcc),
+    mCurIndex(aEnumVariant.mCurIndex) { }
+  virtual ~ChildrenEnumVariant() { }
+
+protected:
+  RefPtr<AccessibleWrap> mAnchorAcc;
+  Accessible* mCurAcc;
+  uint32_t mCurIndex;
+};
+
+} // a11y namespace
+} // mozilla namespace
+
+#endif
diff --git a/accessible/windows/msaa/HTMLTableAccessibleWrap.cpp b/accessible/windows/msaa/HTMLTableAccessibleWrap.cpp
new file mode 100644
index 000000000..13cea8853
--- /dev/null
+++ b/accessible/windows/msaa/HTMLTableAccessibleWrap.cpp
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HTMLTableAccessibleWrap.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLTableAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(HTMLTableAccessibleWrap,
+                             HTMLTableAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(HTMLTableAccessibleWrap,
+                         AccessibleWrap,
+                         ia2AccessibleTable)
+
+void
+HTMLTableAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTable::mTable = nullptr;
+  HTMLTableAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLTableCellAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(HTMLTableCellAccessibleWrap,
+                             HTMLTableCellAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(HTMLTableCellAccessibleWrap,
+                         HyperTextAccessibleWrap,
+                         ia2AccessibleTableCell)
+
+void
+HTMLTableCellAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTableCell::mTableCell = nullptr;
+  HTMLTableCellAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLTableCellAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(HTMLTableHeaderCellAccessibleWrap,
+                             HTMLTableHeaderCellAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(HTMLTableHeaderCellAccessibleWrap,
+                         HyperTextAccessibleWrap,
+                         ia2AccessibleTableCell)
+
+void
+HTMLTableHeaderCellAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTableCell::mTableCell = nullptr;
+  HTMLTableHeaderCellAccessible::Shutdown();
+}
diff --git a/accessible/windows/msaa/HTMLTableAccessibleWrap.h b/accessible/windows/msaa/HTMLTableAccessibleWrap.h
new file mode 100644
index 000000000..71d149a3c
--- /dev/null
+++ b/accessible/windows/msaa/HTMLTableAccessibleWrap.h
@@ -0,0 +1,93 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_HTMLTableAccessibleWrap_h__
+#define mozilla_a11y_HTMLTableAccessibleWrap_h__
+
+#include "HTMLTableAccessible.h"
+
+#include "ia2AccessibleTable.h"
+#include "ia2AccessibleTableCell.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * IA2 wrapper class for HTMLTableAccessible implementing IAccessibleTable
+ * and IAccessibleTable2 interfaces.
+ */
+class HTMLTableAccessibleWrap : public HTMLTableAccessible,
+                                public ia2AccessibleTable
+{
+  ~HTMLTableAccessibleWrap() {}
+
+public:
+  HTMLTableAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    HTMLTableAccessible(aContent, aDoc), ia2AccessibleTable(this)  {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+
+/**
+ * IA2 wrapper class for HTMLTableCellAccessible implementing
+ * IAccessibleTableCell interface.
+ */
+class HTMLTableCellAccessibleWrap : public HTMLTableCellAccessible,
+                                    public ia2AccessibleTableCell
+{
+  ~HTMLTableCellAccessibleWrap() {}
+
+public:
+  HTMLTableCellAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    HTMLTableCellAccessible(aContent, aDoc), ia2AccessibleTableCell(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+
+/**
+ * IA2 wrapper class for HTMLTableHeaderCellAccessible implementing
+ * IAccessibleTableCell interface.
+ */
+class HTMLTableHeaderCellAccessibleWrap : public HTMLTableHeaderCellAccessible,
+                                          public ia2AccessibleTableCell
+{
+  ~HTMLTableHeaderCellAccessibleWrap() {}
+
+public:
+  HTMLTableHeaderCellAccessibleWrap(nsIContent* aContent,
+                                    DocAccessible* aDoc) :
+    HTMLTableHeaderCellAccessible(aContent, aDoc), ia2AccessibleTableCell(this)
+  {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
+
diff --git a/accessible/windows/msaa/HTMLWin32ObjectAccessible.cpp b/accessible/windows/msaa/HTMLWin32ObjectAccessible.cpp
new file mode 100644
index 000000000..3644db68d
--- /dev/null
+++ b/accessible/windows/msaa/HTMLWin32ObjectAccessible.cpp
@@ -0,0 +1,109 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HTMLWin32ObjectAccessible.h"
+
+#include "Role.h"
+#include "States.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLWin32ObjectOwnerAccessible
+////////////////////////////////////////////////////////////////////////////////
+
+HTMLWin32ObjectOwnerAccessible::
+  HTMLWin32ObjectOwnerAccessible(nsIContent* aContent,
+                                 DocAccessible* aDoc, void* aHwnd) :
+  AccessibleWrap(aContent, aDoc), mHwnd(aHwnd)
+{
+  mStateFlags |= eNoKidsFromDOM;
+
+  // Our only child is a HTMLWin32ObjectAccessible object.
+  if (mHwnd) {
+    mNativeAccessible = new HTMLWin32ObjectAccessible(mHwnd, aDoc);
+    AppendChild(mNativeAccessible);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLWin32ObjectOwnerAccessible: Accessible implementation
+
+void
+HTMLWin32ObjectOwnerAccessible::Shutdown()
+{
+  AccessibleWrap::Shutdown();
+  mNativeAccessible = nullptr;
+}
+
+role
+HTMLWin32ObjectOwnerAccessible::NativeRole()
+{
+  return roles::EMBEDDED_OBJECT;
+}
+
+bool
+HTMLWin32ObjectOwnerAccessible::NativelyUnavailable() const
+{
+  // XXX: No HWND means this is windowless plugin which is not accessible in
+  // the meantime.
+  return !mHwnd;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// HTMLWin32ObjectAccessible
+////////////////////////////////////////////////////////////////////////////////
+
+HTMLWin32ObjectAccessible::HTMLWin32ObjectAccessible(void* aHwnd,
+                                                     DocAccessible* aDoc) :
+  DummyAccessible(aDoc)
+{
+  mHwnd = aHwnd;
+  if (mHwnd) {
+#if defined(MOZ_CONTENT_SANDBOX)
+    if (XRE_IsContentProcess()) {
+      DocAccessibleChild* ipcDoc = aDoc->IPCDoc();
+      MOZ_ASSERT(ipcDoc);
+      if (!ipcDoc) {
+        return;
+      }
+
+      IAccessibleHolder proxyHolder;
+      if (!ipcDoc->SendGetWindowedPluginIAccessible(
+              reinterpret_cast<uintptr_t>(mHwnd), &proxyHolder)) {
+        return;
+      }
+
+      mCOMProxy.reset(proxyHolder.Release());
+      return;
+    }
+#endif
+
+    // The plugin is not windowless. In this situation we use 
+    // use its inner child owned by the plugin so that we don't get
+    // in an infinite loop, where the WM_GETOBJECT's get forwarded
+    // back to us and create another HTMLWin32ObjectAccessible
+    mHwnd = ::GetWindow((HWND)aHwnd, GW_CHILD);
+  }
+}
+
+void
+HTMLWin32ObjectAccessible::GetNativeInterface(void** aNativeAccessible)
+{
+#if defined(MOZ_CONTENT_SANDBOX)
+  if (XRE_IsContentProcess()) {
+    RefPtr<IAccessible> addRefed = mCOMProxy.get();
+    addRefed.forget(aNativeAccessible);
+    return;
+  }
+#endif
+
+  if (mHwnd) {
+    ::AccessibleObjectFromWindow(static_cast<HWND>(mHwnd),
+                                 OBJID_WINDOW, IID_IAccessible,
+                                 aNativeAccessible);
+  }
+}
+
diff --git a/accessible/windows/msaa/HTMLWin32ObjectAccessible.h b/accessible/windows/msaa/HTMLWin32ObjectAccessible.h
new file mode 100644
index 000000000..786d52191
--- /dev/null
+++ b/accessible/windows/msaa/HTMLWin32ObjectAccessible.h
@@ -0,0 +1,70 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_HTMLWin32ObjectAccessible_h_
+#define mozilla_a11y_HTMLWin32ObjectAccessible_h_
+
+#include "BaseAccessibles.h"
+
+#if defined(MOZ_CONTENT_SANDBOX)
+#include "mozilla/mscom/Ptr.h"
+#endif
+
+struct IAccessible;
+
+namespace mozilla {
+namespace a11y {
+
+class HTMLWin32ObjectOwnerAccessible : public AccessibleWrap
+{
+public:
+  // This will own the HTMLWin32ObjectAccessible. We create this where the
+  // <object> or <embed> exists in the tree, so that get_accNextSibling() etc.
+  // will still point to Gecko accessible sibling content. This is necessary
+  // because the native plugin accessible doesn't know where it exists in the
+  // Mozilla tree, and returns null for previous and next sibling. This would
+  // have the effect of cutting off all content after the plugin.
+  HTMLWin32ObjectOwnerAccessible(nsIContent* aContent,
+                                 DocAccessible* aDoc, void* aHwnd);
+  virtual ~HTMLWin32ObjectOwnerAccessible() {}
+
+  // Accessible
+  virtual void Shutdown();
+  virtual mozilla::a11y::role NativeRole();
+  virtual bool NativelyUnavailable() const;
+
+protected:
+  void* mHwnd;
+  RefPtr<Accessible> mNativeAccessible;
+};
+
+/**
+  * This class is used only internally, we never! send out an IAccessible linked
+  *   back to this object. This class is used to represent a plugin object when
+  *   referenced as a child or sibling of another Accessible node. We need only
+  *   a limited portion of the Accessible interface implemented here. The
+  *   in depth accessible information will be returned by the actual IAccessible
+  *   object returned by us in Accessible::NewAccessible() that gets the IAccessible
+  *   from the windows system from the window handle.
+  */
+class HTMLWin32ObjectAccessible : public DummyAccessible
+{
+public:
+  HTMLWin32ObjectAccessible(void* aHwnd, DocAccessible* aDoc);
+  virtual ~HTMLWin32ObjectAccessible() {}
+
+  virtual void GetNativeInterface(void** aNativeAccessible) override;
+
+protected:
+  void* mHwnd;
+#if defined(MOZ_CONTENT_SANDBOX)
+  mscom::ProxyUniquePtr<IAccessible> mCOMProxy;
+#endif
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/HyperTextAccessibleWrap.cpp b/accessible/windows/msaa/HyperTextAccessibleWrap.cpp
new file mode 100644
index 000000000..b5fd716d9
--- /dev/null
+++ b/accessible/windows/msaa/HyperTextAccessibleWrap.cpp
@@ -0,0 +1,67 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "HyperTextAccessibleWrap.h"
+#include "Accessible-inl.h"
+
+#include "nsEventShell.h"
+
+#include "mozilla/StaticPtr.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+NS_IMPL_ISUPPORTS_INHERITED0(HyperTextAccessibleWrap,
+                             HyperTextAccessible)
+
+STDMETHODIMP
+HyperTextAccessibleWrap::QueryInterface(REFIID aIID, void** aInstancePtr)
+{
+  if (!aInstancePtr)
+    return E_FAIL;
+
+  *aInstancePtr = nullptr;
+
+  if (IsTextRole()) {
+    if (aIID == IID_IAccessibleText)
+      *aInstancePtr =
+        static_cast<IAccessibleText*>(static_cast<ia2AccessibleText*>(this));
+    else if (aIID == IID_IAccessibleHypertext)
+      *aInstancePtr = static_cast<IAccessibleHypertext*>(this);
+    else if (aIID == IID_IAccessibleEditableText)
+      *aInstancePtr = static_cast<IAccessibleEditableText*>(this);
+
+    if (*aInstancePtr) {
+      AddRef();
+      return S_OK;
+    }
+  }
+
+  return AccessibleWrap::QueryInterface(aIID, aInstancePtr);
+}
+
+nsresult
+HyperTextAccessibleWrap::HandleAccEvent(AccEvent* aEvent)
+{
+  uint32_t eventType = aEvent->GetEventType();
+
+  if (eventType == nsIAccessibleEvent::EVENT_TEXT_REMOVED ||
+      eventType == nsIAccessibleEvent::EVENT_TEXT_INSERTED) {
+    Accessible* accessible = aEvent->GetAccessible();
+    if (accessible && accessible->IsHyperText()) {
+      AccTextChangeEvent* event = downcast_accEvent(aEvent);
+        HyperTextAccessibleWrap* text =
+          static_cast<HyperTextAccessibleWrap*>(accessible->AsHyperText());
+      ia2AccessibleText::UpdateTextChangeData(text, event->IsTextInserted(),
+                                              event->ModifiedText(),
+                                              event->GetStartOffset(),
+                                              event->GetLength());
+    }
+  }
+
+  return HyperTextAccessible::HandleAccEvent(aEvent);
+}
diff --git a/accessible/windows/msaa/HyperTextAccessibleWrap.h b/accessible/windows/msaa/HyperTextAccessibleWrap.h
new file mode 100644
index 000000000..c0f853da2
--- /dev/null
+++ b/accessible/windows/msaa/HyperTextAccessibleWrap.h
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_HyperTextAccessibleWrap_h__
+#define mozilla_a11y_HyperTextAccessibleWrap_h__
+
+#include "HyperTextAccessible.h"
+#include "ia2AccessibleEditableText.h"
+#include "ia2AccessibleHypertext.h"
+#include "IUnknownImpl.h"
+
+namespace mozilla {
+template<class T> class StaticAutoPtr;
+template<class T> class StaticRefPtr;
+
+namespace a11y {
+
+class HyperTextAccessibleWrap : public HyperTextAccessible,
+                                public ia2AccessibleHypertext,
+                                public ia2AccessibleEditableText
+{
+public:
+  HyperTextAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    HyperTextAccessible(aContent, aDoc) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  // Accessible
+  virtual nsresult HandleAccEvent(AccEvent* aEvent);
+
+protected:
+  ~HyperTextAccessibleWrap() {}
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/IDSet.h b/accessible/windows/msaa/IDSet.h
new file mode 100644
index 000000000..3c3ed74c3
--- /dev/null
+++ b/accessible/windows/msaa/IDSet.h
@@ -0,0 +1,136 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * A class to generate unique IDs in the range [ - 2^31, 0 )
+ */
+
+#ifndef MOZILLA_A11Y_IDSet_h_
+#define MOZILLA_A11Y_IDSet_h_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/MathAlgorithms.h"
+#include "mozilla/SplayTree.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * On windows an accessible's id must be a negative 32 bit integer. It is
+ * important to support recycling arbitrary IDs because accessibles can be
+ * created and destroyed at any time in the life of a page.  IDSet provides 2
+ * operations: generate an ID in the range (0, mMaxId], and release an ID so
+ * it can be allocated again.  Allocated ID are tracked by a sparse bitmap
+ * implemented with a splay tree.  Nodes in the tree are keyed by the upper N
+ * bits of the ID, and the node contains a bitmap tracking the allocation of
+ * 2^(ceil(log2(mMaxId)) - N) IDs.
+ *
+ * Note that negation is handled by MsaaIdGenerator as it performs additional
+ * decoration on the ID generated by IDSet.
+ * @see mozilla::a11y::MsaaIdGenerator
+ */
+class IDSet
+{
+public:
+  constexpr explicit IDSet(const uint32_t aMaxIdBits)
+    : mBitSet()
+    , mIdx(0)
+    , mMaxId((1UL << aMaxIdBits) - 1UL)
+    , mMaxIdx(mMaxId / bitsPerElt)
+  {
+  }
+
+  /**
+   * Return a new unique id.
+   */
+  uint32_t GetID()
+  {
+    uint32_t idx = mIdx;
+    while (true) {
+      BitSetElt* elt = mBitSet.findOrInsert(BitSetElt(idx));
+      if (elt->mBitvec[0] != UINT64_MAX) {
+        uint32_t i = CountTrailingZeroes64(~elt->mBitvec[0]);
+
+        elt->mBitvec[0] |= (1ull << i);
+        mIdx = idx;
+        return (elt->mIdx * bitsPerElt + i);
+      }
+
+      if (elt->mBitvec[1] != UINT64_MAX) {
+        uint32_t i = CountTrailingZeroes64(~elt->mBitvec[1]);
+
+        elt->mBitvec[1] |= (1ull << i);
+        mIdx = idx;
+        return (elt->mIdx * bitsPerElt + bitsPerWord + i);
+      }
+
+      idx++;
+      if (idx > mMaxIdx) {
+        idx = 0;
+      }
+
+      if (idx == mIdx) {
+        MOZ_CRASH("used up all the available ids");
+      }
+    }
+  }
+
+  /**
+   * Free a no longer required id so it may be allocated again.
+   */
+  void ReleaseID(uint32_t aID)
+  {
+    MOZ_ASSERT(aID < mMaxId);
+
+    uint32_t idx = aID / bitsPerElt;
+    mIdx = idx;
+    BitSetElt* elt = mBitSet.find(BitSetElt(idx));
+    MOZ_ASSERT(elt);
+
+    uint32_t vecIdx = (aID % bitsPerElt) / bitsPerWord;
+    elt->mBitvec[vecIdx] &= ~(1ull << (aID % bitsPerWord));
+    if (elt->mBitvec[0] == 0 && elt->mBitvec[1] == 0) {
+      delete mBitSet.remove(*elt);
+    }
+  }
+
+private:
+  static const unsigned int wordsPerElt = 2;
+  static const unsigned int bitsPerWord = 64;
+  static const unsigned int bitsPerElt = wordsPerElt * bitsPerWord;
+
+  struct BitSetElt : mozilla::SplayTreeNode<BitSetElt>
+  {
+    explicit BitSetElt(uint32_t aIdx) :
+      mIdx(aIdx)
+    { mBitvec[0] = mBitvec[1] = 0; }
+
+    uint64_t mBitvec[wordsPerElt];
+    uint32_t mIdx;
+
+    static int compare(const BitSetElt& a, const BitSetElt& b)
+    {
+      if (a.mIdx == b.mIdx) {
+        return 0;
+      }
+
+      if (a.mIdx < b.mIdx) {
+        return -1;
+      }
+      return 1;
+    }
+  };
+
+  SplayTree<BitSetElt, BitSetElt> mBitSet;
+  uint32_t mIdx;
+  const uint32_t mMaxId;
+  const uint32_t mMaxIdx;
+};
+
+}
+}
+
+#endif
diff --git a/accessible/windows/msaa/IUnknownImpl.cpp b/accessible/windows/msaa/IUnknownImpl.cpp
new file mode 100644
index 000000000..4a9fa5383
--- /dev/null
+++ b/accessible/windows/msaa/IUnknownImpl.cpp
@@ -0,0 +1,58 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. *
+ */
+
+#include "IUnknownImpl.h"
+
+#include "nsDebug.h"
+
+#ifdef MOZ_CRASHREPORTER
+#include "nsExceptionHandler.h"
+#endif
+
+namespace mozilla {
+namespace a11y {
+
+HRESULT
+GetHRESULT(nsresult aResult)
+{
+  switch (aResult) {
+    case NS_OK:
+      return S_OK;
+
+    case NS_ERROR_INVALID_ARG:
+      return E_INVALIDARG;
+
+    case NS_ERROR_OUT_OF_MEMORY:
+      return E_OUTOFMEMORY;
+
+    case NS_ERROR_NOT_IMPLEMENTED:
+      return E_NOTIMPL;
+
+    default:
+      return E_FAIL;
+  }
+}
+
+int
+FilterExceptions(unsigned int aCode, EXCEPTION_POINTERS* aExceptionInfo)
+{
+  if (aCode == EXCEPTION_ACCESS_VIOLATION) {
+#ifdef MOZ_CRASHREPORTER
+    // MSAA swallows crashes (because it is COM-based) but we still need to
+    // learn about those crashes so we can fix them. Make sure to pass them to
+    // the crash reporter.
+    CrashReporter::WriteMinidumpForException(aExceptionInfo);
+#endif
+  } else {
+    NS_NOTREACHED("We should only be catching crash exceptions");
+  }
+
+  return EXCEPTION_CONTINUE_SEARCH;
+}
+
+} // namespace a11y
+} // namespace mozilla
diff --git a/accessible/windows/msaa/IUnknownImpl.h b/accessible/windows/msaa/IUnknownImpl.h
new file mode 100644
index 000000000..dbf6c1374
--- /dev/null
+++ b/accessible/windows/msaa/IUnknownImpl.h
@@ -0,0 +1,192 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. *
+ */
+
+#ifndef mozilla_a11y_IUnknownImpl_h_
+#define mozilla_a11y_IUnknownImpl_h_
+
+#include <windows.h>
+#undef CreateEvent // thank you windows you're such a helper
+#include "nsError.h"
+
+// Avoid warning C4509 like "nonstandard extension used:
+// 'AccessibleWrap::[acc_getName]' uses SEH and 'name' has destructor.
+// At this point we're catching a crash which is of much greater
+// importance than the missing dereference for the nsCOMPtr<>
+#ifdef _MSC_VER
+#pragma warning( disable : 4509 )
+#endif
+
+#ifdef __GNUC__
+#define ATTRIBUTE_UNUSED __attribute__((unused))
+#else
+#define ATTRIBUTE_UNUSED
+#endif
+
+namespace mozilla {
+namespace a11y {
+
+class AutoRefCnt
+{
+public:
+  AutoRefCnt() : mValue(0) {}
+
+  ULONG operator++() { return ++mValue; }
+  ULONG operator--() { return --mValue; }
+  ULONG operator++(int) { return ++mValue; }
+  ULONG operator--(int) { return --mValue; }
+
+  operator ULONG() const { return mValue; }
+
+private:
+  ULONG mValue;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#define DECL_IUNKNOWN                                                          \
+public:                                                                        \
+  virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, void**);            \
+  virtual ULONG STDMETHODCALLTYPE AddRef() final                               \
+  {                                                                            \
+    MOZ_ASSERT(int32_t(mRefCnt) >= 0, "illegal refcnt");                       \
+    ++mRefCnt;                                                                 \
+    return mRefCnt;                                                            \
+  }                                                                            \
+  virtual ULONG STDMETHODCALLTYPE Release() final                              \
+  {                                                                            \
+     MOZ_ASSERT(int32_t(mRefCnt) > 0, "dup release");                          \
+     --mRefCnt;                                                                \
+     if (mRefCnt)                                                              \
+       return mRefCnt;                                                         \
+                                                                               \
+     delete this;                                                              \
+     return 0;                                                                 \
+  }                                                                            \
+private:                                                                       \
+  mozilla::a11y::AutoRefCnt mRefCnt;                                           \
+public:
+
+#define DECL_IUNKNOWN_INHERITED                                                \
+public:                                                                        \
+virtual HRESULT STDMETHODCALLTYPE QueryInterface(REFIID, void**);              \
+
+#define IMPL_IUNKNOWN_QUERY_HEAD(Class)                                        \
+STDMETHODIMP                                                                   \
+Class::QueryInterface(REFIID aIID, void** aInstancePtr)                        \
+{                                                                              \
+  A11Y_TRYBLOCK_BEGIN                                                          \
+  if (!aInstancePtr)                                                           \
+    return E_INVALIDARG;                                                       \
+  *aInstancePtr = nullptr;                                                     \
+                                                                               \
+  HRESULT hr ATTRIBUTE_UNUSED = E_NOINTERFACE;
+
+#define IMPL_IUNKNOWN_QUERY_TAIL                                               \
+  return hr;                                                                   \
+  A11Y_TRYBLOCK_END                                                            \
+}
+
+#define IMPL_IUNKNOWN_QUERY_TAIL_AGGREGATED(Member)                            \
+  return Member->QueryInterface(aIID, aInstancePtr);                           \
+  A11Y_TRYBLOCK_END                                                            \
+}
+
+#define IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(BaseClass)                          \
+  return BaseClass::QueryInterface(aIID, aInstancePtr);                        \
+  A11Y_TRYBLOCK_END                                                            \
+}
+
+#define IMPL_IUNKNOWN_QUERY_IFACE(Iface)                                       \
+  if (aIID == IID_##Iface) {                                                   \
+    *aInstancePtr = static_cast<Iface*>(this);                                 \
+    AddRef();                                                                  \
+    return S_OK;                                                               \
+  }
+
+#define IMPL_IUNKNOWN_QUERY_IFACE_AMBIGIOUS(Iface, aResolveIface)              \
+  if (aIID == IID_##Iface) {                                                   \
+    *aInstancePtr = static_cast<Iface*>(static_cast<aResolveIface*>(this));    \
+    AddRef();                                                                  \
+    return S_OK;                                                               \
+  }
+
+#define IMPL_IUNKNOWN_QUERY_CLASS(Class)                                       \
+  hr = Class::QueryInterface(aIID, aInstancePtr);                              \
+  if (SUCCEEDED(hr))                                                           \
+    return hr;
+
+#define IMPL_IUNKNOWN_QUERY_CLASS_COND(Class, Cond)                            \
+  if (Cond) {                                                                  \
+    hr = Class::QueryInterface(aIID, aInstancePtr);                            \
+    if (SUCCEEDED(hr))                                                         \
+      return hr;                                                               \
+  }
+
+#define IMPL_IUNKNOWN_QUERY_AGGR_COND(Member, Cond)                            \
+  if (Cond) {                                                                  \
+    hr = Member->QueryInterface(aIID, aInstancePtr);                           \
+    if (SUCCEEDED(hr))                                                         \
+      return hr;                                                               \
+  }
+
+#define IMPL_IUNKNOWN1(Class, I1)                                              \
+  IMPL_IUNKNOWN_QUERY_HEAD(Class)                                              \
+  IMPL_IUNKNOWN_QUERY_IFACE(I1);                                               \
+  IMPL_IUNKNOWN_QUERY_IFACE(IUnknown);                                         \
+  IMPL_IUNKNOWN_QUERY_TAIL                                                     \
+
+#define IMPL_IUNKNOWN2(Class, I1, I2)                                          \
+  IMPL_IUNKNOWN_QUERY_HEAD(Class)                                              \
+  IMPL_IUNKNOWN_QUERY_IFACE(I1);                                               \
+  IMPL_IUNKNOWN_QUERY_IFACE(I2);                                               \
+  IMPL_IUNKNOWN_QUERY_IFACE_AMBIGIOUS(IUnknown, I1);                           \
+  IMPL_IUNKNOWN_QUERY_TAIL                                                     \
+
+#define IMPL_IUNKNOWN_INHERITED1(Class, Super0, Super1)                        \
+  IMPL_IUNKNOWN_QUERY_HEAD(Class)                                              \
+  IMPL_IUNKNOWN_QUERY_CLASS(Super1);                                           \
+  IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(Super0)
+
+#define IMPL_IUNKNOWN_INHERITED2(Class, Super0, Super1, Super2)                \
+  IMPL_IUNKNOWN_QUERY_HEAD(Class)                                              \
+  IMPL_IUNKNOWN_QUERY_CLASS(Super1);                                           \
+  IMPL_IUNKNOWN_QUERY_CLASS(Super2);                                           \
+  IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(Super0)
+
+
+/**
+ * Wrap every method body by these macroses to pass exception to the crash
+ * reporter.
+ */
+#define A11Y_TRYBLOCK_BEGIN                                                    \
+  MOZ_SEH_TRY {
+
+#define A11Y_TRYBLOCK_END                                                      \
+  } MOZ_SEH_EXCEPT(mozilla::a11y::FilterExceptions(::GetExceptionCode(),       \
+                                                   GetExceptionInformation())) \
+  { }                                                                          \
+  return E_FAIL;
+
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * Converts nsresult to HRESULT.
+ */
+HRESULT GetHRESULT(nsresult aResult);
+
+/**
+ * Used to pass an exception to the crash reporter.
+ */
+int FilterExceptions(unsigned int aCode, EXCEPTION_POINTERS* aExceptionInfo);
+
+} // namespace a11y;
+} //namespace mozilla;
+
+#endif
diff --git a/accessible/windows/msaa/ImageAccessibleWrap.cpp b/accessible/windows/msaa/ImageAccessibleWrap.cpp
new file mode 100644
index 000000000..7ff2e8a47
--- /dev/null
+++ b/accessible/windows/msaa/ImageAccessibleWrap.cpp
@@ -0,0 +1,20 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ImageAccessibleWrap.h"
+#include "nsIURI.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+
+NS_IMPL_ISUPPORTS_INHERITED0(ImageAccessibleWrap,
+                             ImageAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(ImageAccessibleWrap,
+                         AccessibleWrap,
+                         ia2AccessibleImage)
+
diff --git a/accessible/windows/msaa/ImageAccessibleWrap.h b/accessible/windows/msaa/ImageAccessibleWrap.h
new file mode 100644
index 000000000..e6a916ebe
--- /dev/null
+++ b/accessible/windows/msaa/ImageAccessibleWrap.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_ImageAccessibleWrap_h__
+#define mozilla_a11y_ImageAccessibleWrap_h__
+
+#include "ImageAccessible.h"
+#include "ia2AccessibleImage.h"
+
+namespace mozilla {
+namespace a11y {
+
+class ImageAccessibleWrap : public ImageAccessible,
+                            public ia2AccessibleImage
+{
+public:
+  ImageAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    ImageAccessible(aContent, aDoc) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+protected:
+  ~ImageAccessibleWrap() {}
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
+
diff --git a/accessible/windows/msaa/MsaaIdGenerator.cpp b/accessible/windows/msaa/MsaaIdGenerator.cpp
new file mode 100644
index 000000000..5f4b333fa
--- /dev/null
+++ b/accessible/windows/msaa/MsaaIdGenerator.cpp
@@ -0,0 +1,243 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MsaaIdGenerator.h"
+
+#include "mozilla/a11y/AccessibleWrap.h"
+#include "mozilla/ClearOnShutdown.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/StaticPtr.h"
+#include "mozilla/Unused.h"
+#include "nsDataHashtable.h"
+#include "nsIXULRuntime.h"
+
+// These constants may be adjusted to modify the proportion of the Child ID
+// allocated to the content ID vs proportion allocated to the unique ID. They
+// must always sum to 31, ie. the width of a 32-bit integer less the sign bit.
+
+// NB: kNumContentProcessIDBits must be large enough to successfully hold the
+// maximum permitted number of e10s content processes. If the e10s maximum
+// number of content processes changes, then kNumContentProcessIDBits must also
+// be updated if necessary to accommodate that new value!
+static const uint32_t kNumContentProcessIDBits = 7UL;
+static const uint32_t kNumUniqueIDBits = (31UL - kNumContentProcessIDBits);
+
+static_assert(kNumContentProcessIDBits + kNumUniqueIDBits == 31,
+              "Allocation of Content ID bits and Unique ID bits must sum to 31");
+
+namespace mozilla {
+namespace a11y {
+namespace detail {
+
+typedef nsDataHashtable<nsUint64HashKey, uint32_t> ContentParentIdMap;
+
+#pragma pack(push, 1)
+union MsaaID
+{
+  int32_t mInt32;
+  uint32_t mUInt32;
+  struct
+  {
+    uint32_t mUniqueID:kNumUniqueIDBits;
+    uint32_t mContentProcessID:kNumContentProcessIDBits;
+    uint32_t mSignBit:1;
+  }
+  mCracked;
+};
+#pragma pack(pop)
+
+static uint32_t
+BuildMsaaID(const uint32_t aID, const uint32_t aContentProcessID)
+{
+  MsaaID id;
+  id.mCracked.mSignBit = 0;
+  id.mCracked.mUniqueID = aID;
+  id.mCracked.mContentProcessID = aContentProcessID;
+  return ~id.mUInt32;
+}
+
+class MsaaIDCracker
+{
+public:
+  explicit MsaaIDCracker(const uint32_t aMsaaID)
+  {
+    mID.mUInt32 = ~aMsaaID;
+  }
+
+  uint32_t GetContentProcessId()
+  {
+    return mID.mCracked.mContentProcessID;
+  }
+
+  uint32_t GetUniqueId()
+  {
+    return mID.mCracked.mUniqueID;
+  }
+
+private:
+  MsaaID  mID;
+};
+
+} // namespace detail
+
+constexpr MsaaIdGenerator::MsaaIdGenerator()
+  : mIDSet(kNumUniqueIDBits)
+{}
+
+uint32_t
+MsaaIdGenerator::GetID()
+{
+  uint32_t id = mIDSet.GetID();
+  MOZ_ASSERT(id <= ((1UL << kNumUniqueIDBits) - 1UL));
+  return detail::BuildMsaaID(id, ResolveContentProcessID());
+}
+
+void
+MsaaIdGenerator::ReleaseID(AccessibleWrap* aAccWrap)
+{
+  MOZ_ASSERT(aAccWrap);
+  uint32_t id = aAccWrap->GetExistingID();
+  MOZ_ASSERT(id != AccessibleWrap::kNoID);
+  detail::MsaaIDCracker cracked(id);
+  if (cracked.GetContentProcessId() != ResolveContentProcessID()) {
+    // This may happen if chrome holds a proxy whose ID was originally generated
+    // by a content process. Since ReleaseID only has meaning in the process
+    // that originally generated that ID, we ignore ReleaseID calls for any ID
+    // that did not come from the current process.
+    MOZ_ASSERT(aAccWrap->IsProxy());
+    return;
+  }
+  mIDSet.ReleaseID(cracked.GetUniqueId());
+}
+
+bool
+MsaaIdGenerator::IsChromeID(uint32_t aID)
+{
+  detail::MsaaIDCracker cracked(aID);
+  return cracked.GetContentProcessId() == 0;
+}
+
+bool
+MsaaIdGenerator::IsIDForThisContentProcess(uint32_t aID)
+{
+  MOZ_ASSERT(XRE_IsContentProcess());
+  detail::MsaaIDCracker cracked(aID);
+  return cracked.GetContentProcessId() == ResolveContentProcessID();
+}
+
+bool
+MsaaIdGenerator::IsIDForContentProcess(uint32_t aID,
+                                       dom::ContentParentId aIPCContentProcessId)
+{
+  MOZ_ASSERT(XRE_IsParentProcess());
+  detail::MsaaIDCracker cracked(aID);
+  return cracked.GetContentProcessId() ==
+           GetContentProcessIDFor(aIPCContentProcessId);
+}
+
+bool
+MsaaIdGenerator::IsSameContentProcessFor(uint32_t aFirstID, uint32_t aSecondID)
+{
+  detail::MsaaIDCracker firstCracked(aFirstID);
+  detail::MsaaIDCracker secondCracked(aSecondID);
+  return firstCracked.GetContentProcessId() ==
+           secondCracked.GetContentProcessId();
+}
+
+uint32_t
+MsaaIdGenerator::ResolveContentProcessID()
+{
+  if (XRE_IsParentProcess()) {
+    return 0;
+  }
+
+  dom::ContentChild* contentChild = dom::ContentChild::GetSingleton();
+  uint32_t result = contentChild->GetMsaaID();
+
+  MOZ_ASSERT(result);
+  return result;
+}
+
+/**
+ * Each dom::ContentParent has a 64-bit ID. This ID is monotonically increasing
+ * with each new content process, so those IDs are effectively single-use. OTOH,
+ * MSAA requires 32-bit IDs. Since we only allocate kNumContentProcessIDBits for
+ * the content process ID component, the MSAA content process ID value must be
+ * reusable. sContentParentIdMap holds the current associations between
+ * dom::ContentParent IDs and the MSAA content parent IDs that have been
+ * allocated to them.
+ */
+static StaticAutoPtr<detail::ContentParentIdMap> sContentParentIdMap;
+
+static const uint32_t kBitsPerByte = 8UL;
+// Set sContentProcessIdBitmap[0] to 1 to reserve the Chrome process's id
+static uint64_t sContentProcessIdBitmap[(1UL << kNumContentProcessIDBits) /
+                                        (sizeof(uint64_t) * kBitsPerByte)] = {1ULL};
+static const uint32_t kBitsPerElement = sizeof(sContentProcessIdBitmap[0]) *
+                                        kBitsPerByte;
+
+uint32_t
+MsaaIdGenerator::GetContentProcessIDFor(dom::ContentParentId aIPCContentProcessID)
+{
+  MOZ_ASSERT(XRE_IsParentProcess() && NS_IsMainThread());
+  if (!sContentParentIdMap) {
+    sContentParentIdMap = new detail::ContentParentIdMap();
+    ClearOnShutdown(&sContentParentIdMap);
+  }
+
+  uint32_t value = 0;
+  if (sContentParentIdMap->Get(aIPCContentProcessID, &value)) {
+    return value;
+  }
+
+  uint32_t index = 0;
+  for (; index < ArrayLength(sContentProcessIdBitmap); ++index) {
+    if (sContentProcessIdBitmap[index] == UINT64_MAX) {
+      continue;
+    }
+    uint32_t bitIndex = CountTrailingZeroes64(~sContentProcessIdBitmap[index]);
+    MOZ_ASSERT(!(sContentProcessIdBitmap[index] & (1ULL << bitIndex)));
+    MOZ_ASSERT(bitIndex != 0 || index != 0);
+    sContentProcessIdBitmap[index] |= (1ULL << bitIndex);
+    value = index * kBitsPerElement + bitIndex;
+    break;
+  }
+
+  // If we run out of content process IDs, we're in trouble
+  MOZ_RELEASE_ASSERT(index < ArrayLength(sContentProcessIdBitmap));
+
+  sContentParentIdMap->Put(aIPCContentProcessID, value);
+  return value;
+}
+
+void
+MsaaIdGenerator::ReleaseContentProcessIDFor(dom::ContentParentId aIPCContentProcessID)
+{
+  MOZ_ASSERT(XRE_IsParentProcess() && NS_IsMainThread());
+  if (!sContentParentIdMap) {
+    // Since Content IDs are generated lazily, ContentParent might attempt
+    // to release an ID that was never allocated to begin with.
+    return;
+  }
+
+  Maybe<uint32_t> mapping = sContentParentIdMap->GetAndRemove(aIPCContentProcessID);
+  if (!mapping) {
+    // Since Content IDs are generated lazily, ContentParent might attempt
+    // to release an ID that was never allocated to begin with.
+    return;
+  }
+
+  uint32_t index = mapping.ref() / kBitsPerElement;
+  MOZ_ASSERT(index < ArrayLength(sContentProcessIdBitmap));
+
+  uint64_t mask = 1ULL << (mapping.ref() % kBitsPerElement);
+  MOZ_ASSERT(sContentProcessIdBitmap[index] & mask);
+
+  sContentProcessIdBitmap[index] &= ~mask;
+}
+
+} // namespace a11y
+} // namespace mozilla
diff --git a/accessible/windows/msaa/MsaaIdGenerator.h b/accessible/windows/msaa/MsaaIdGenerator.h
new file mode 100644
index 000000000..b845e8473
--- /dev/null
+++ b/accessible/windows/msaa/MsaaIdGenerator.h
@@ -0,0 +1,56 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_MsaaIdGenerator_h
+#define mozilla_a11y_MsaaIdGenerator_h
+
+#include "mozilla/a11y/IDSet.h"
+
+#include "mozilla/dom/ipc/IdType.h"
+
+namespace mozilla {
+namespace a11y {
+
+class AccessibleWrap;
+
+/**
+ * This class is responsible for generating child IDs used by our MSAA
+ * implementation. Since e10s requires us to differentiate IDs based on the
+ * originating process of the accessible, a portion of the ID's bits are
+ * allocated to storing that information. The remaining bits represent the
+ * unique ID of the accessible, within that content process.
+ *
+ * The constants kNumContentProcessIDBits and kNumUniqueIDBits in the
+ * implementation are responsible for determining the proportion of bits that
+ * are allocated for each purpose.
+ */
+class MsaaIdGenerator
+{
+public:
+  constexpr MsaaIdGenerator();
+
+  uint32_t GetID();
+  void ReleaseID(AccessibleWrap* aAccWrap);
+  bool IsChromeID(uint32_t aID);
+  bool IsIDForThisContentProcess(uint32_t aID);
+  bool IsIDForContentProcess(uint32_t aID,
+                             dom::ContentParentId aIPCContentProcessId);
+  bool IsSameContentProcessFor(uint32_t aFirstID, uint32_t aSecondID);
+
+  uint32_t GetContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);
+  void ReleaseContentProcessIDFor(dom::ContentParentId aIPCContentProcessID);
+
+private:
+  uint32_t ResolveContentProcessID();
+
+private:
+  IDSet     mIDSet;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif // mozilla_a11y_MsaaIdGenerator_h
diff --git a/accessible/windows/msaa/Platform.cpp b/accessible/windows/msaa/Platform.cpp
new file mode 100644
index 000000000..dc6acd3ad
--- /dev/null
+++ b/accessible/windows/msaa/Platform.cpp
@@ -0,0 +1,147 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Platform.h"
+
+#include "AccEvent.h"
+#include "Compatibility.h"
+#include "HyperTextAccessibleWrap.h"
+#include "ia2AccessibleText.h"
+#include "nsIXULRuntime.h"
+#include "nsWinUtils.h"
+#include "mozilla/a11y/ProxyAccessible.h"
+#include "mozilla/mscom/InterceptorLog.h"
+#include "mozilla/mscom/Registration.h"
+#include "mozilla/StaticPtr.h"
+#include "ProxyWrappers.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+using namespace mozilla::mscom;
+
+static StaticAutoPtr<RegisteredProxy> gRegProxy;
+static StaticAutoPtr<RegisteredProxy> gRegAccTlb;
+static StaticAutoPtr<RegisteredProxy> gRegMiscTlb;
+
+void
+a11y::PlatformInit()
+{
+  Compatibility::Init();
+
+  nsWinUtils::MaybeStartWindowEmulation();
+  ia2AccessibleText::InitTextChangeData();
+  if (BrowserTabsRemoteAutostart()) {
+    mscom::InterceptorLog::Init();
+    UniquePtr<RegisteredProxy> regProxy(
+        mscom::RegisterProxy(L"ia2marshal.dll"));
+    gRegProxy = regProxy.release();
+    UniquePtr<RegisteredProxy> regAccTlb(
+        mscom::RegisterTypelib(L"oleacc.dll",
+                               RegistrationFlags::eUseSystemDirectory));
+    gRegAccTlb = regAccTlb.release();
+    UniquePtr<RegisteredProxy> regMiscTlb(
+        mscom::RegisterTypelib(L"Accessible.tlb"));
+    gRegMiscTlb = regMiscTlb.release();
+  }
+}
+
+void
+a11y::PlatformShutdown()
+{
+  ::DestroyCaret();
+
+  nsWinUtils::ShutdownWindowEmulation();
+  gRegProxy = nullptr;
+  gRegAccTlb = nullptr;
+  gRegMiscTlb = nullptr;
+}
+
+void
+a11y::ProxyCreated(ProxyAccessible* aProxy, uint32_t aInterfaces)
+{
+  AccessibleWrap* wrapper = nullptr;
+  if (aInterfaces & Interfaces::DOCUMENT) {
+    wrapper = new DocProxyAccessibleWrap(aProxy);
+  } else if (aInterfaces & Interfaces::HYPERTEXT) {
+    wrapper = new HyperTextProxyAccessibleWrap(aProxy);
+  } else {
+    wrapper = new ProxyAccessibleWrap(aProxy);
+  }
+
+  wrapper->SetProxyInterfaces(aInterfaces);
+  wrapper->AddRef();
+  aProxy->SetWrapper(reinterpret_cast<uintptr_t>(wrapper));
+}
+
+void
+a11y::ProxyDestroyed(ProxyAccessible* aProxy)
+{
+  AccessibleWrap* wrapper =
+    reinterpret_cast<AccessibleWrap*>(aProxy->GetWrapper());
+  MOZ_ASSERT(wrapper);
+  if (!wrapper)
+    return;
+
+  wrapper->Shutdown();
+  aProxy->SetWrapper(0);
+  wrapper->Release();
+}
+
+void
+a11y::ProxyEvent(ProxyAccessible* aTarget, uint32_t aEventType)
+{
+  AccessibleWrap::FireWinEvent(WrapperFor(aTarget), aEventType);
+}
+
+void
+a11y::ProxyStateChangeEvent(ProxyAccessible* aTarget, uint64_t, bool)
+{
+  AccessibleWrap::FireWinEvent(WrapperFor(aTarget),
+                               nsIAccessibleEvent::EVENT_STATE_CHANGE);
+}
+
+void
+a11y::ProxyCaretMoveEvent(ProxyAccessible* aTarget, int32_t aOffset)
+{
+  AccessibleWrap::FireWinEvent(WrapperFor(aTarget),
+                               nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED);
+}
+
+void
+a11y::ProxyTextChangeEvent(ProxyAccessible* aText, const nsString& aStr,
+                           int32_t aStart, uint32_t aLen, bool aInsert, bool)
+{
+  AccessibleWrap* wrapper = WrapperFor(aText);
+  MOZ_ASSERT(wrapper);
+  if (!wrapper) {
+    return;
+  }
+
+  auto text = static_cast<HyperTextAccessibleWrap*>(wrapper->AsHyperText());
+  if (text) {
+    ia2AccessibleText::UpdateTextChangeData(text, aInsert, aStr, aStart, aLen);
+  }
+
+  uint32_t eventType = aInsert ? nsIAccessibleEvent::EVENT_TEXT_INSERTED :
+    nsIAccessibleEvent::EVENT_TEXT_REMOVED;
+  AccessibleWrap::FireWinEvent(wrapper, eventType);
+}
+
+void
+a11y::ProxyShowHideEvent(ProxyAccessible* aTarget, ProxyAccessible*, bool aInsert, bool)
+{
+  uint32_t event = aInsert ? nsIAccessibleEvent::EVENT_SHOW :
+    nsIAccessibleEvent::EVENT_HIDE;
+  AccessibleWrap* wrapper = WrapperFor(aTarget);
+  AccessibleWrap::FireWinEvent(wrapper, event);
+}
+
+void
+a11y::ProxySelectionEvent(ProxyAccessible* aTarget, ProxyAccessible*, uint32_t aType)
+{
+  AccessibleWrap* wrapper = WrapperFor(aTarget);
+  AccessibleWrap::FireWinEvent(wrapper, aType);
+}
diff --git a/accessible/windows/msaa/RootAccessibleWrap.cpp b/accessible/windows/msaa/RootAccessibleWrap.cpp
new file mode 100644
index 000000000..30fe40c43
--- /dev/null
+++ b/accessible/windows/msaa/RootAccessibleWrap.cpp
@@ -0,0 +1,45 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "RootAccessibleWrap.h"
+
+#include "Compatibility.h"
+#include "nsCoreUtils.h"
+#include "nsWinUtils.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// Constructor/destructor
+
+RootAccessibleWrap::
+  RootAccessibleWrap(nsIDocument* aDocument, nsIPresShell* aPresShell) :
+  RootAccessible(aDocument, aPresShell)
+{
+}
+
+RootAccessibleWrap::~RootAccessibleWrap()
+{
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// RootAccessible
+
+void
+RootAccessibleWrap::DocumentActivated(DocAccessible* aDocument)
+{
+  if (Compatibility::IsDolphin() &&
+      nsCoreUtils::IsTabDocument(aDocument->DocumentNode())) {
+    uint32_t count = mChildDocuments.Length();
+    for (uint32_t idx = 0; idx < count; idx++) {
+      DocAccessible* childDoc = mChildDocuments[idx];
+      HWND childDocHWND = static_cast<HWND>(childDoc->GetNativeWindow());
+      if (childDoc != aDocument)
+        nsWinUtils::HideNativeWindow(childDocHWND);
+      else
+        nsWinUtils::ShowNativeWindow(childDocHWND);
+    }
+  }
+}
diff --git a/accessible/windows/msaa/RootAccessibleWrap.h b/accessible/windows/msaa/RootAccessibleWrap.h
new file mode 100644
index 000000000..6aa6fefe3
--- /dev/null
+++ b/accessible/windows/msaa/RootAccessibleWrap.h
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_RootAccessibleWrap_h__
+#define mozilla_a11y_RootAccessibleWrap_h__
+
+#include "RootAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+class RootAccessibleWrap : public RootAccessible
+{
+public:
+  RootAccessibleWrap(nsIDocument* aDocument, nsIPresShell* aPresShell);
+  virtual ~RootAccessibleWrap();
+
+  // RootAccessible
+  virtual void DocumentActivated(DocAccessible* aDocument);
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/ServiceProvider.cpp b/accessible/windows/msaa/ServiceProvider.cpp
new file mode 100644
index 000000000..82265d3c2
--- /dev/null
+++ b/accessible/windows/msaa/ServiceProvider.cpp
@@ -0,0 +1,96 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ServiceProvider.h"
+
+#include "ApplicationAccessibleWrap.h"
+#include "Compatibility.h"
+#include "DocAccessible.h"
+#include "nsAccUtils.h"
+#include "nsCoreUtils.h"
+#include "Relation.h"
+#include "uiaRawElmProvider.h"
+
+#include "mozilla/Preferences.h"
+#include "nsIDocShell.h"
+
+#include "ISimpleDOMNode_i.c"
+
+namespace mozilla {
+namespace a11y {
+
+IMPL_IUNKNOWN_QUERY_HEAD(ServiceProvider)
+  IMPL_IUNKNOWN_QUERY_IFACE(IServiceProvider)
+IMPL_IUNKNOWN_QUERY_TAIL_AGGREGATED(mAccessible)
+
+
+////////////////////////////////////////////////////////////////////////////////
+// IServiceProvider
+
+STDMETHODIMP
+ServiceProvider::QueryService(REFGUID aGuidService, REFIID aIID,
+                              void** aInstancePtr)
+{
+  if (!aInstancePtr)
+    return E_INVALIDARG;
+
+  *aInstancePtr = nullptr;
+
+  // UIA IAccessibleEx
+  if (aGuidService == IID_IAccessibleEx &&
+      Preferences::GetBool("accessibility.uia.enable")) {
+    uiaRawElmProvider* accEx = new uiaRawElmProvider(mAccessible);
+    HRESULT hr = accEx->QueryInterface(aIID, aInstancePtr);
+    if (FAILED(hr))
+      delete accEx;
+
+    return hr;
+  }
+
+  // Provide a special service ID for getting the accessible for the browser tab
+  // document that contains this accessible object. If this accessible object
+  // is not inside a browser tab then the service fails with E_NOINTERFACE.
+  // A use case for this is for screen readers that need to switch context or
+  // 'virtual buffer' when focus moves from one browser tab area to another.
+  static const GUID SID_IAccessibleContentDocument =
+    { 0xa5d8e1f3,0x3571,0x4d8f,{0x95,0x21,0x07,0xed,0x28,0xfb,0x07,0x2e} };
+  if (aGuidService == SID_IAccessibleContentDocument) {
+    if (aIID != IID_IAccessible)
+      return E_NOINTERFACE;
+
+    Relation rel = mAccessible->RelationByType(RelationType::CONTAINING_TAB_PANE);
+    AccessibleWrap* tabDoc = static_cast<AccessibleWrap*>(rel.Next());
+    if (!tabDoc)
+      return E_NOINTERFACE;
+
+    *aInstancePtr = static_cast<IAccessible*>(tabDoc);
+    (reinterpret_cast<IUnknown*>(*aInstancePtr))->AddRef();
+    return S_OK;
+  }
+
+  // Can get to IAccessibleApplication from any node via QS
+  if (aGuidService == IID_IAccessibleApplication ||
+      (Compatibility::IsJAWS() && aIID == IID_IAccessibleApplication)) {
+    ApplicationAccessibleWrap* applicationAcc =
+      static_cast<ApplicationAccessibleWrap*>(ApplicationAcc());
+    if (!applicationAcc)
+      return E_NOINTERFACE;
+
+    return applicationAcc->QueryInterface(aIID, aInstancePtr);
+  }
+
+  static const GUID IID_SimpleDOMDeprecated =
+    { 0x0c539790,0x12e4,0x11cf,{0xb6,0x61,0x00,0xaa,0x00,0x4c,0xd6,0xd8} };
+  if (aGuidService == IID_ISimpleDOMNode ||
+      aGuidService == IID_SimpleDOMDeprecated ||
+      aGuidService == IID_IAccessible ||  aGuidService == IID_IAccessible2)
+    return mAccessible->QueryInterface(aIID, aInstancePtr);
+
+  return E_INVALIDARG;
+}
+
+} // namespace a11y
+} // namespace mozilla
diff --git a/accessible/windows/msaa/ServiceProvider.h b/accessible/windows/msaa/ServiceProvider.h
new file mode 100644
index 000000000..b0fc812c5
--- /dev/null
+++ b/accessible/windows/msaa/ServiceProvider.h
@@ -0,0 +1,38 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_ServiceProvider_h_
+#define mozilla_a11y_ServiceProvider_h_
+
+#include <servprov.h>
+
+#include "AccessibleWrap.h"
+#include "IUnknownImpl.h"
+
+namespace mozilla {
+namespace a11y {
+
+class ServiceProvider final : public IServiceProvider
+{
+public:
+  ServiceProvider(AccessibleWrap* aAcc) : mAccessible(aAcc) {}
+  ~ServiceProvider() {}
+
+  DECL_IUNKNOWN
+
+  // IServiceProvider
+  virtual HRESULT STDMETHODCALLTYPE QueryService(REFGUID aGuidService,
+                                                 REFIID aIID,
+                                                 void** aInstancePtr);
+
+private:
+  RefPtr<AccessibleWrap> mAccessible;
+};
+
+}
+}
+
+#endif
diff --git a/accessible/windows/msaa/TextLeafAccessibleWrap.cpp b/accessible/windows/msaa/TextLeafAccessibleWrap.cpp
new file mode 100644
index 000000000..6f1d193db
--- /dev/null
+++ b/accessible/windows/msaa/TextLeafAccessibleWrap.cpp
@@ -0,0 +1,21 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "TextLeafAccessibleWrap.h"
+
+#include "sdnTextAccessible.h"
+#include "Statistics.h"
+
+using namespace mozilla::a11y;
+
+IMPL_IUNKNOWN_QUERY_HEAD(TextLeafAccessibleWrap)
+  if (aIID == IID_ISimpleDOMText) {
+    statistics::ISimpleDOMUsed();
+    *aInstancePtr = static_cast<ISimpleDOMText*>(new sdnTextAccessible(this));
+    static_cast<IUnknown*>(*aInstancePtr)->AddRef();
+    return S_OK;
+  }
+IMPL_IUNKNOWN_QUERY_TAIL_INHERITED(AccessibleWrap)
diff --git a/accessible/windows/msaa/TextLeafAccessibleWrap.h b/accessible/windows/msaa/TextLeafAccessibleWrap.h
new file mode 100644
index 000000000..612bed173
--- /dev/null
+++ b/accessible/windows/msaa/TextLeafAccessibleWrap.h
@@ -0,0 +1,33 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_TextLeafAccessibleWrap_h__
+#define mozilla_a11y_TextLeafAccessibleWrap_h__
+
+#include "TextLeafAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * Wrap TextLeafAccessible to expose ISimpleDOMText as a native interface with
+ * a tear off.
+ */
+class TextLeafAccessibleWrap : public TextLeafAccessible
+{
+public:
+  TextLeafAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    TextLeafAccessible(aContent, aDoc) { }
+  virtual ~TextLeafAccessibleWrap() {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/XULListboxAccessibleWrap.cpp b/accessible/windows/msaa/XULListboxAccessibleWrap.cpp
new file mode 100644
index 000000000..4bd0fb512
--- /dev/null
+++ b/accessible/windows/msaa/XULListboxAccessibleWrap.cpp
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "XULListboxAccessibleWrap.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// XULListboxAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(XULListboxAccessibleWrap,
+                             XULListboxAccessible)
+
+IMPL_IUNKNOWN_QUERY_HEAD(XULListboxAccessibleWrap)
+IMPL_IUNKNOWN_QUERY_CLASS_COND(ia2AccessibleTable,
+                               !IsDefunct() && IsMulticolumn());
+IMPL_IUNKNOWN_QUERY_CLASS(AccessibleWrap)
+IMPL_IUNKNOWN_QUERY_TAIL
+
+void
+XULListboxAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTable::mTable = nullptr;
+  XULListboxAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// XULListCellAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(XULListCellAccessibleWrap,
+                             XULListCellAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(XULListCellAccessibleWrap,
+                         HyperTextAccessibleWrap,
+                         ia2AccessibleTableCell)
+
+void
+XULListCellAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTableCell::mTableCell = nullptr;
+  XULListCellAccessible::Shutdown();
+}
diff --git a/accessible/windows/msaa/XULListboxAccessibleWrap.h b/accessible/windows/msaa/XULListboxAccessibleWrap.h
new file mode 100644
index 000000000..37db2d70a
--- /dev/null
+++ b/accessible/windows/msaa/XULListboxAccessibleWrap.h
@@ -0,0 +1,64 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_XULListboxAccessibleWrap_h__
+#define mozilla_a11y_XULListboxAccessibleWrap_h__
+
+#include "XULListboxAccessible.h"
+
+#include "ia2AccessibleTable.h"
+#include "ia2AccessibleTableCell.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * IA2 wrapper class for XULListboxAccessible class implementing
+ * IAccessibleTable and IAccessibleTable2 interfaces.
+ */
+class XULListboxAccessibleWrap : public XULListboxAccessible,
+                                 public ia2AccessibleTable
+{
+  ~XULListboxAccessibleWrap() {}
+
+public:
+  XULListboxAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    XULListboxAccessible(aContent, aDoc), ia2AccessibleTable(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+/**
+ * IA2 wrapper class for XULListCellAccessible class, implements
+ * IAccessibleTableCell interface.
+ */
+class XULListCellAccessibleWrap : public XULListCellAccessible,
+                                  public ia2AccessibleTableCell
+{
+  ~XULListCellAccessibleWrap() {}
+
+public:
+  XULListCellAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+    XULListCellAccessible(aContent, aDoc), ia2AccessibleTableCell(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/XULMenuAccessibleWrap.cpp b/accessible/windows/msaa/XULMenuAccessibleWrap.cpp
new file mode 100644
index 000000000..ba0075bac
--- /dev/null
+++ b/accessible/windows/msaa/XULMenuAccessibleWrap.cpp
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "XULMenuAccessibleWrap.h"
+#include "nsNameSpaceManager.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// XULMenuAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+XULMenuitemAccessibleWrap::
+  XULMenuitemAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc) :
+  XULMenuitemAccessible(aContent, aDoc)
+{
+}
+
+ENameValueFlag
+XULMenuitemAccessibleWrap::Name(nsString& aName)
+{
+  // XXX This should be done in MSAA's get_accName() so that Accessible::Name()]
+  // provides the same results on all platforms
+  XULMenuitemAccessible::Name(aName);
+  if (aName.IsEmpty())
+    return eNameOK;
+
+  nsAutoString accel;
+  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::acceltext, accel);
+  if (!accel.IsEmpty())
+    aName += NS_LITERAL_STRING("\t") + accel;
+
+  return eNameOK;
+}
diff --git a/accessible/windows/msaa/XULMenuAccessibleWrap.h b/accessible/windows/msaa/XULMenuAccessibleWrap.h
new file mode 100644
index 000000000..a07182241
--- /dev/null
+++ b/accessible/windows/msaa/XULMenuAccessibleWrap.h
@@ -0,0 +1,27 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_XULMenuAccessibleWrap_h__
+#define mozilla_a11y_XULMenuAccessibleWrap_h__
+
+#include "XULMenuAccessible.h"
+
+namespace mozilla {
+namespace a11y {
+
+class XULMenuitemAccessibleWrap : public XULMenuitemAccessible
+{
+public:
+  XULMenuitemAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc);
+  virtual ~XULMenuitemAccessibleWrap() {}
+
+  // nsIAccessible
+  virtual mozilla::a11y::ENameValueFlag Name(nsString& aName);
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/XULTreeGridAccessibleWrap.cpp b/accessible/windows/msaa/XULTreeGridAccessibleWrap.cpp
new file mode 100644
index 000000000..e5cc4a09b
--- /dev/null
+++ b/accessible/windows/msaa/XULTreeGridAccessibleWrap.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "XULTreeGridAccessibleWrap.h"
+
+using namespace mozilla::a11y;
+
+////////////////////////////////////////////////////////////////////////////////
+// XULTreeGridAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(XULTreeGridAccessibleWrap,
+                             XULTreeGridAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(XULTreeGridAccessibleWrap,
+                         AccessibleWrap,
+                         ia2AccessibleTable)
+
+void
+XULTreeGridAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTable::mTable = nullptr;
+  XULTreeGridAccessible::Shutdown();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// XULTreeGridCellAccessibleWrap
+////////////////////////////////////////////////////////////////////////////////
+
+NS_IMPL_ISUPPORTS_INHERITED0(XULTreeGridCellAccessibleWrap,
+                             XULTreeGridCellAccessible)
+
+IMPL_IUNKNOWN_INHERITED1(XULTreeGridCellAccessibleWrap,
+                         AccessibleWrap,
+                         ia2AccessibleTableCell)
+
+void
+XULTreeGridCellAccessibleWrap::Shutdown()
+{
+  ia2AccessibleTableCell::mTableCell = nullptr;
+  XULTreeGridCellAccessible::Shutdown();
+}
diff --git a/accessible/windows/msaa/XULTreeGridAccessibleWrap.h b/accessible/windows/msaa/XULTreeGridAccessibleWrap.h
new file mode 100644
index 000000000..3c6c62699
--- /dev/null
+++ b/accessible/windows/msaa/XULTreeGridAccessibleWrap.h
@@ -0,0 +1,71 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef mozilla_a11y_XULTreeGridAccessibleWrap_h__
+#define mozilla_a11y_XULTreeGridAccessibleWrap_h__
+
+#include "XULTreeGridAccessible.h"
+
+#include "ia2AccessibleTable.h"
+#include "ia2AccessibleTableCell.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * IA2 wrapper class for XULTreeGridAccessible class implementing
+ * IAccessibleTable and IAccessibleTable2 interfaces.
+ */
+class XULTreeGridAccessibleWrap : public XULTreeGridAccessible,
+                                  public ia2AccessibleTable
+{
+  ~XULTreeGridAccessibleWrap() {}
+
+public:
+  XULTreeGridAccessibleWrap(nsIContent* aContent, DocAccessible* aDoc,
+                            nsTreeBodyFrame* aTree) :
+    XULTreeGridAccessible(aContent, aDoc, aTree), ia2AccessibleTable(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+/**
+ * IA2 wrapper class for XULTreeGridCellAccessible class, implements
+ * IAccessibleTableCell interface.
+ */
+class XULTreeGridCellAccessibleWrap : public XULTreeGridCellAccessible,
+                                      public ia2AccessibleTableCell
+{
+  ~XULTreeGridCellAccessibleWrap() {}
+
+public:
+  XULTreeGridCellAccessibleWrap(nsIContent* aContent,
+                                DocAccessible* aDoc,
+                                XULTreeGridRowAccessible* aRowAcc,
+                                nsITreeBoxObject* aTree,
+                                nsITreeView* aTreeView,
+                                int32_t aRow, nsITreeColumn* aColumn) :
+    XULTreeGridCellAccessible(aContent, aDoc, aRowAcc, aTree, aTreeView, aRow,
+                              aColumn), ia2AccessibleTableCell(this) {}
+
+  // IUnknown
+  DECL_IUNKNOWN_INHERITED
+
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
+
+  virtual void Shutdown() override;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif
diff --git a/accessible/windows/msaa/moz.build b/accessible/windows/msaa/moz.build
new file mode 100644
index 000000000..54c8c6686
--- /dev/null
+++ b/accessible/windows/msaa/moz.build
@@ -0,0 +1,76 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS += [
+    'IUnknownImpl.h',
+]
+
+EXPORTS.mozilla.a11y += [
+    'AccessibleWrap.h',
+    'Compatibility.h',
+    'HyperTextAccessibleWrap.h',
+    'IDSet.h',
+    'MsaaIdGenerator.h',
+]
+
+UNIFIED_SOURCES += [
+    'AccessibleWrap.cpp',
+    'ApplicationAccessibleWrap.cpp',
+    'ARIAGridAccessibleWrap.cpp',
+    'Compatibility.cpp',
+    'DocAccessibleWrap.cpp',
+    'EnumVariant.cpp',
+    'HTMLTableAccessibleWrap.cpp',
+    'HTMLWin32ObjectAccessible.cpp',
+    'HyperTextAccessibleWrap.cpp',
+    'ImageAccessibleWrap.cpp',
+    'IUnknownImpl.cpp',
+    'MsaaIdGenerator.cpp',
+    'nsWinUtils.cpp',
+    'Platform.cpp',
+    'RootAccessibleWrap.cpp',
+    'TextLeafAccessibleWrap.cpp',
+]
+
+# This file cannot be built in unified mode because it includes ISimpleDOMNode_i.c.
+SOURCES += [
+    'ServiceProvider.cpp',
+]
+
+if CONFIG['MOZ_XUL']:
+    UNIFIED_SOURCES += [
+        'XULListboxAccessibleWrap.cpp',
+        'XULMenuAccessibleWrap.cpp',
+        'XULTreeGridAccessibleWrap.cpp',
+    ]
+
+LOCAL_INCLUDES += [
+    '/accessible/base',
+    '/accessible/generic',
+    '/accessible/html',
+    '/accessible/ipc',
+    '/accessible/ipc/win',
+    '/accessible/windows',
+    '/accessible/windows/ia2',
+    '/accessible/windows/sdn',
+    '/accessible/windows/uia',
+    '/accessible/xpcom',
+    '/accessible/xul',
+    '/dom/base',
+    '/layout/style',
+]
+
+# The Windows MIDL code generator creates things like:
+#
+#   #endif !_MIDL_USE_GUIDDEF_
+#
+# which clang-cl complains about.  MSVC doesn't, so turn this warning off.
+if CONFIG['CLANG_CL']:
+    CXXFLAGS += ['-Wno-extra-tokens']
+
+include('/ipc/chromium/chromium-config.mozbuild')
+
+FINAL_LIBRARY = 'xul'
diff --git a/accessible/windows/msaa/nsEventMap.h b/accessible/windows/msaa/nsEventMap.h
new file mode 100644
index 000000000..8af992e1c
--- /dev/null
+++ b/accessible/windows/msaa/nsEventMap.h
@@ -0,0 +1,103 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* vim:expandtab:shiftwidth=4:tabstop=4:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <winuser.h>
+#include "AccessibleEventId.h"
+
+const uint32_t kEVENT_WIN_UNKNOWN = 0x00000000;
+
+static const uint32_t gWinEventMap[] = {
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent doesn't have 0 constant
+  EVENT_OBJECT_SHOW,                                 // nsIAccessibleEvent::EVENT_SHOW
+  EVENT_OBJECT_HIDE,                                 // nsIAccessibleEvent::EVENT_HIDE
+  EVENT_OBJECT_REORDER,                              // nsIAccessibleEvent::EVENT_REORDER
+  IA2_EVENT_ACTIVE_DECENDENT_CHANGED,                // nsIAccessibleEvent::EVENT_ACTIVE_DECENDENT_CHANGED
+  EVENT_OBJECT_FOCUS,                                // nsIAccessibleEvent::EVENT_FOCUS
+  EVENT_OBJECT_STATECHANGE,                          // nsIAccessibleEvent::EVENT_STATE_CHANGE
+  EVENT_OBJECT_LOCATIONCHANGE,                       // nsIAccessibleEvent::EVENT_LOCATION_CHANGE
+  EVENT_OBJECT_NAMECHANGE,                           // nsIAccessibleEvent::EVENT_NAME_CHANGE
+  EVENT_OBJECT_DESCRIPTIONCHANGE,                    // nsIAccessibleEvent::EVENT_DESCRIPTION_CHANGE
+  EVENT_OBJECT_VALUECHANGE,                          // nsIAccessibleEvent::EVENT_VALUE_CHANGE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_HELP_CHANGE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_DEFACTION_CHANGE
+  IA2_EVENT_ACTION_CHANGED,                          // nsIAccessibleEvent::EVENT_ACTION_CHANGE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_ACCELERATOR_CHANGE
+  EVENT_OBJECT_SELECTION,                            // nsIAccessibleEvent::EVENT_SELECTION
+  EVENT_OBJECT_SELECTIONADD,                         // nsIAccessibleEvent::EVENT_SELECTION_ADD
+  EVENT_OBJECT_SELECTIONREMOVE,                      // nsIAccessibleEvent::EVENT_SELECTION_REMOVE
+  EVENT_OBJECT_SELECTIONWITHIN,                      // nsIAccessibleEvent::EVENT_SELECTION_WITHIN
+  EVENT_SYSTEM_ALERT,                                // nsIAccessibleEvent::EVENT_ALERT
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_FOREGROUND
+  EVENT_SYSTEM_MENUSTART,                            // nsIAccessibleEvent::EVENT_MENU_START
+  EVENT_SYSTEM_MENUEND,                              // nsIAccessibleEvent::EVENT_MENU_END
+  EVENT_SYSTEM_MENUPOPUPSTART,                       // nsIAccessibleEvent::EVENT_MENUPOPUP_START
+  EVENT_SYSTEM_MENUPOPUPEND,                         // nsIAccessibleEvent::EVENT_MENUPOPUP_END
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_CAPTURE_START
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_CAPTURE_END
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_MOVESIZE_START
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_MOVESIZE_END
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_CONTEXT_HELP_START
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_CONTEXT_HELP_END
+  EVENT_SYSTEM_DRAGDROPSTART,                        // nsIAccessibleEvent::EVENT_DRAGDROP_START
+  EVENT_SYSTEM_DRAGDROPEND,                          // nsIAccessibleEvent::EVENT_DRAGDROP_END
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_DIALOG_START
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_DIALOG_END
+  EVENT_SYSTEM_SCROLLINGSTART,                       // nsIAccessibleEvent::EVENT_SCROLLING_START
+  EVENT_SYSTEM_SCROLLINGEND,                         // nsIAccessibleEvent::EVENT_SCROLLING_END
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_MINIMIZE_START
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_MINIMIZE_END
+  IA2_EVENT_DOCUMENT_LOAD_COMPLETE,                  // nsIAccessibleEvent::EVENT_DOCUMENT_LOAD_COMPLETE
+  IA2_EVENT_DOCUMENT_RELOAD,                         // nsIAccessibleEvent::EVENT_DOCUMENT_RELOAD
+  IA2_EVENT_DOCUMENT_LOAD_STOPPED,                   // nsIAccessibleEvent::EVENT_DOCUMENT_LOAD_STOPPED
+  IA2_EVENT_DOCUMENT_ATTRIBUTE_CHANGED,              // nsIAccessibleEvent::EVENT_DOCUMENT_ATTRIBUTES_CHANGED
+  IA2_EVENT_DOCUMENT_CONTENT_CHANGED,                // nsIAccessibleEvent::EVENT_DOCUMENT_CONTENT_CHANGED
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_PROPERTY_CHANGED
+  IA2_EVENT_PAGE_CHANGED,                            // nsIAccessibleEvent::IA2_EVENT_PAGE_CHANGED
+  IA2_EVENT_TEXT_ATTRIBUTE_CHANGED,                  // nsIAccessibleEvent::EVENT_TEXT_ATTRIBUTE_CHANGED
+  IA2_EVENT_TEXT_CARET_MOVED,                        // nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED
+  IA2_EVENT_TEXT_CHANGED,                            // nsIAccessibleEvent::EVENT_TEXT_CHANGED
+  IA2_EVENT_TEXT_INSERTED,                           // nsIAccessibleEvent::EVENT_TEXT_INSERTED
+  IA2_EVENT_TEXT_REMOVED,                            // nsIAccessibleEvent::EVENT_TEXT_REMOVED
+  IA2_EVENT_TEXT_UPDATED,                            // nsIAccessibleEvent::EVENT_TEXT_UPDATED
+  IA2_EVENT_TEXT_SELECTION_CHANGED,                  // nsIAccessibleEvent::EVENT_TEXT_SELECTION_CHANGED
+  IA2_EVENT_VISIBLE_DATA_CHANGED,                    // nsIAccessibleEvent::EVENT_VISIBLE_DATA_CHANGED
+  IA2_EVENT_TEXT_COLUMN_CHANGED,                     // nsIAccessibleEvent::EVENT_TEXT_COLUMN_CHANGED
+  IA2_EVENT_SECTION_CHANGED,                         // nsIAccessibleEvent::EVENT_SECTION_CHANGED
+  IA2_EVENT_TABLE_CAPTION_CHANGED,                   // nsIAccessibleEvent::EVENT_TABLE_CAPTION_CHANGED
+  IA2_EVENT_TABLE_MODEL_CHANGED,                     // nsIAccessibleEvent::EVENT_TABLE_MODEL_CHANGED
+  IA2_EVENT_TABLE_SUMMARY_CHANGED,                   // nsIAccessibleEvent::EVENT_TABLE_SUMMARY_CHANGED
+  IA2_EVENT_TABLE_ROW_DESCRIPTION_CHANGED,           // nsIAccessibleEvent::EVENT_TABLE_ROW_DESCRIPTION_CHANGED
+  IA2_EVENT_TABLE_ROW_HEADER_CHANGED,                // nsIAccessibleEvent::EVENT_TABLE_ROW_HEADER_CHANGED
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_ROW_INSERT
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_ROW_DELETE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_ROW_REORDER
+  IA2_EVENT_TABLE_COLUMN_DESCRIPTION_CHANGED,        // nsIAccessibleEvent::EVENT_TABLE_COLUMN_DESCRIPTION_CHANGED
+  IA2_EVENT_TABLE_COLUMN_HEADER_CHANGED,             // nsIAccessibleEvent::EVENT_TABLE_COLUMN_HEADER_CHANGED
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_COLUMN_INSERT
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_COLUMN_DELETE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_TABLE_COLUMN_REORDER
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_ACTIVATE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_CREATE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_DEACTIVATE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_DESTROY
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_MAXIMIZE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_MINIMIZE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_RESIZE
+  kEVENT_WIN_UNKNOWN,                                // nsIAccessibleEvent::EVENT_WINDOW_RESTORE
+  IA2_EVENT_HYPERLINK_END_INDEX_CHANGED,             // nsIAccessibleEvent::EVENT_HYPERLINK_END_INDEX_CHANGED
+  IA2_EVENT_HYPERLINK_NUMBER_OF_ANCHORS_CHANGED,     // nsIAccessibleEvent::EVENT_HYPERLINK_NUMBER_OF_ANCHORS_CHANGED
+  IA2_EVENT_HYPERLINK_SELECTED_LINK_CHANGED,         // nsIAccessibleEvent::EVENT_HYPERLINK_SELECTED_LINK_CHANGED
+  IA2_EVENT_HYPERTEXT_LINK_ACTIVATED,                // nsIAccessibleEvent::EVENT_HYPERTEXT_LINK_ACTIVATED
+  IA2_EVENT_HYPERTEXT_LINK_SELECTED,                 // nsIAccessibleEvent::EVENT_HYPERTEXT_LINK_SELECTED
+  IA2_EVENT_HYPERLINK_START_INDEX_CHANGED,           // nsIAccessibleEvent::EVENT_HYPERLINK_START_INDEX_CHANGED
+  IA2_EVENT_HYPERTEXT_CHANGED,                       // nsIAccessibleEvent::EVENT_HYPERTEXT_CHANGED
+  IA2_EVENT_HYPERTEXT_NLINKS_CHANGED,                // nsIAccessibleEvent::EVENT_HYPERTEXT_NLINKS_CHANGED
+  IA2_EVENT_OBJECT_ATTRIBUTE_CHANGED,                // nsIAccessibleEvent::EVENT_OBJECT_ATTRIBUTE_CHANGED
+  kEVENT_WIN_UNKNOWN,                                 // nsIAccessibleEvent::EVENT_VIRTUALCURSOR_CHANGED
+  EVENT_OBJECT_VALUECHANGE                          // nsIAccessibleEvent::EVENT_TEXT_VALUE_CHANGE
+};
+
diff --git a/accessible/windows/msaa/nsWinUtils.cpp b/accessible/windows/msaa/nsWinUtils.cpp
new file mode 100644
index 000000000..b49cd0263
--- /dev/null
+++ b/accessible/windows/msaa/nsWinUtils.cpp
@@ -0,0 +1,181 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWinUtils.h"
+
+#include "Compatibility.h"
+#include "DocAccessible.h"
+#include "nsAccessibilityService.h"
+#include "nsCoreUtils.h"
+
+#include "mozilla/Preferences.h"
+#include "nsArrayUtils.h"
+#include "nsIArray.h"
+#include "nsICSSDeclaration.h"
+#include "nsIDocument.h"
+#include "nsIDocShellTreeItem.h"
+#include "mozilla/dom/Element.h"
+#include "nsXULAppAPI.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+using mozilla::dom::Element;
+
+// Window property used by ipc related code in identifying accessible
+// tab windows.
+const wchar_t* kPropNameTabContent = L"AccessibleTabWindow";
+
+/**
+ * WindowProc to process WM_GETOBJECT messages, used in windows emulation mode.
+ */
+static LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg,
+                                   WPARAM wParam, LPARAM lParam);
+
+bool nsWinUtils::sWindowEmulationStarted = false;
+
+already_AddRefed<nsIDOMCSSStyleDeclaration>
+nsWinUtils::GetComputedStyleDeclaration(nsIContent* aContent)
+{
+  nsIContent* elm = nsCoreUtils::GetDOMElementFor(aContent);
+  if (!elm)
+    return nullptr;
+
+  // Returns number of items in style declaration
+  nsCOMPtr<nsPIDOMWindowInner> window = elm->OwnerDoc()->GetInnerWindow();
+  if (!window)
+    return nullptr;
+
+  ErrorResult dummy;
+  nsCOMPtr<nsICSSDeclaration> cssDecl;
+  nsCOMPtr<Element> domElement(do_QueryInterface(elm));
+  cssDecl = window->GetComputedStyle(*domElement, EmptyString(), dummy);
+  nsCOMPtr<nsIDOMCSSStyleDeclaration> domDecl = do_QueryInterface(cssDecl);
+  dummy.SuppressException();
+  return domDecl.forget();
+}
+
+bool
+nsWinUtils::MaybeStartWindowEmulation()
+{
+  // Register window class that'll be used for document accessibles associated
+  // with tabs.
+  if (IPCAccessibilityActive())
+    return false;
+
+  if (Compatibility::IsJAWS() || Compatibility::IsWE() ||
+      Compatibility::IsDolphin() ||
+      XRE_IsContentProcess()) {
+    RegisterNativeWindow(kClassNameTabContent);
+    sWindowEmulationStarted = true;
+    return true;
+  }
+
+  return false;
+}
+
+void
+nsWinUtils::ShutdownWindowEmulation()
+{
+  // Unregister window call that's used for document accessibles associated
+  // with tabs.
+  if (IsWindowEmulationStarted()) {
+    ::UnregisterClassW(kClassNameTabContent, GetModuleHandle(nullptr));
+    sWindowEmulationStarted = false;
+  }
+}
+
+void
+nsWinUtils::RegisterNativeWindow(LPCWSTR aWindowClass)
+{
+  WNDCLASSW wc;
+  wc.style = CS_GLOBALCLASS;
+  wc.lpfnWndProc = WindowProc;
+  wc.cbClsExtra = 0;
+  wc.cbWndExtra = 0;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.hIcon = nullptr;
+  wc.hCursor = nullptr;
+  wc.hbrBackground = nullptr;
+  wc.lpszMenuName = nullptr;
+  wc.lpszClassName = aWindowClass;
+  ::RegisterClassW(&wc);
+}
+
+HWND
+nsWinUtils::CreateNativeWindow(LPCWSTR aWindowClass, HWND aParentWnd,
+                               int aX, int aY, int aWidth, int aHeight,
+                               bool aIsActive)
+{
+  HWND hwnd = ::CreateWindowExW(WS_EX_TRANSPARENT, aWindowClass,
+                                L"NetscapeDispatchWnd",
+                                WS_CHILD | (aIsActive ? WS_VISIBLE : 0),
+                                aX, aY, aWidth, aHeight,
+                                aParentWnd,
+                                nullptr,
+                                GetModuleHandle(nullptr),
+                                nullptr);
+  if (hwnd) {
+    // Mark this window so that ipc related code can identify it.
+    ::SetPropW(hwnd, kPropNameTabContent, (HANDLE)1);
+  }
+  return hwnd;
+}
+
+void
+nsWinUtils::ShowNativeWindow(HWND aWnd)
+{
+  ::ShowWindow(aWnd, SW_SHOW);
+}
+
+void
+nsWinUtils::HideNativeWindow(HWND aWnd)
+{
+  ::SetWindowPos(aWnd, nullptr, 0, 0, 0, 0,
+                 SWP_HIDEWINDOW | SWP_NOSIZE | SWP_NOMOVE |
+                 SWP_NOZORDER | SWP_NOACTIVATE);
+}
+
+LRESULT CALLBACK
+WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+  // Note, this window's message handling should not invoke any call that
+  // may result in a cross-process ipc call. Doing so may violate RPC
+  // message semantics.
+
+  switch (msg) {
+    case WM_GETOBJECT:
+    {
+      // Do explicit casting to make it working on 64bit systems (see bug 649236
+      // for details).
+      int32_t objId = static_cast<DWORD>(lParam);
+      if (objId == OBJID_CLIENT) {
+        DocAccessible* document =
+          reinterpret_cast<DocAccessible*>(::GetPropW(hWnd, kPropNameDocAcc));
+        if (document) {
+          IAccessible* msaaAccessible = nullptr;
+          document->GetNativeInterface((void**)&msaaAccessible); // does an addref
+          if (msaaAccessible) {
+            LRESULT result = ::LresultFromObject(IID_IAccessible, wParam,
+                                                 msaaAccessible); // does an addref
+            msaaAccessible->Release(); // release extra addref
+            return result;
+          }
+        }
+      }
+      return 0;
+    }
+    case WM_NCHITTEST:
+    {
+      LRESULT lRet = ::DefWindowProc(hWnd, msg, wParam, lParam);
+      if (HTCLIENT == lRet)
+        lRet = HTTRANSPARENT;
+      return lRet;
+    }
+  }
+
+  return ::DefWindowProcW(hWnd, msg, wParam, lParam);
+}
diff --git a/accessible/windows/msaa/nsWinUtils.h b/accessible/windows/msaa/nsWinUtils.h
new file mode 100644
index 000000000..55089e722
--- /dev/null
+++ b/accessible/windows/msaa/nsWinUtils.h
@@ -0,0 +1,86 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsWinUtils_h_
+#define nsWinUtils_h_
+
+#include <windows.h>
+
+#include "nsIDOMCSSStyleDeclaration.h"
+#include "nsCOMPtr.h"
+
+class nsIContent;
+
+namespace mozilla {
+namespace a11y {
+
+class DocAccessible;
+
+const LPCWSTR kClassNameRoot = L"MozillaUIWindowClass";
+const LPCWSTR kClassNameTabContent = L"MozillaContentWindowClass";
+const LPCWSTR kPropNameDocAcc = L"MozDocAccessible";
+
+class nsWinUtils
+{
+public:
+  /**
+   * Return computed styles declaration for the given node.
+   *
+   * @note Please use it carefully since it can shutdown the accessible tree
+   *       you operate on.
+   */
+  static already_AddRefed<nsIDOMCSSStyleDeclaration>
+    GetComputedStyleDeclaration(nsIContent* aContent);
+
+  /**
+   * Start window emulation if presence of specific AT is detected.
+   */
+  static bool MaybeStartWindowEmulation();
+
+  /**
+   * Free resources used for window emulation.
+   */
+  static void ShutdownWindowEmulation();
+
+  /**
+   * Return true if window emulation is started.
+   */
+  static bool IsWindowEmulationStarted() { return sWindowEmulationStarted; }
+
+  /**
+   * Helper to register window class.
+   */
+  static void RegisterNativeWindow(LPCWSTR aWindowClass);
+
+  /**
+   * Helper to create a window.
+   */
+  static HWND CreateNativeWindow(LPCWSTR aWindowClass, HWND aParentWnd,
+                                 int aX, int aY, int aWidth, int aHeight,
+                                 bool aIsActive);
+
+  /**
+   * Helper to show window.
+   */
+  static void ShowNativeWindow(HWND aWnd);
+
+  /**
+   * Helper to hide window.
+   */
+  static void HideNativeWindow(HWND aWnd);
+
+private:
+  /**
+   * Flag that indicates if window emulation is started.
+   */
+  static bool sWindowEmulationStarted;
+};
+
+} // namespace a11y
+} // namespace mozilla
+
+#endif