Add m-esr52 at 52.6.0

1 files changed, 1686 insertions, 0 deletions

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);
+}