Add m-esr52 at 52.6.0

1 files changed, 3326 insertions, 0 deletions

diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
new file mode 100644
index 000000000..b820fed3c
--- /dev/null
+++ b/widget/nsBaseWidget.cpp
@@ -0,0 +1,3326 @@
+/* -*- 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 "mozilla/ArrayUtils.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/TextEventDispatcher.h"
+#include "mozilla/TextEventDispatcherListener.h"
+
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "mozilla/layers/CompositorBridgeParent.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "nsBaseWidget.h"
+#include "nsDeviceContext.h"
+#include "nsCOMPtr.h"
+#include "nsGfxCIID.h"
+#include "nsWidgetsCID.h"
+#include "nsServiceManagerUtils.h"
+#include "nsIKeyEventInPluginCallback.h"
+#include "nsIScreenManager.h"
+#include "nsAppDirectoryServiceDefs.h"
+#include "nsISimpleEnumerator.h"
+#include "nsIContent.h"
+#include "nsIDocument.h"
+#include "nsIPresShell.h"
+#include "nsIServiceManager.h"
+#include "mozilla/Preferences.h"
+#include "BasicLayers.h"
+#include "ClientLayerManager.h"
+#include "mozilla/layers/Compositor.h"
+#include "nsIXULRuntime.h"
+#include "nsIXULWindow.h"
+#include "nsIBaseWindow.h"
+#include "nsXULPopupManager.h"
+#include "nsIWidgetListener.h"
+#include "nsIGfxInfo.h"
+#include "npapi.h"
+#include "X11UndefineNone.h"
+#include "base/thread.h"
+#include "prdtoa.h"
+#include "prenv.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/Unused.h"
+#include "nsContentUtils.h"
+#include "gfxPrefs.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/MouseEvents.h"
+#include "GLConsts.h"
+#include "mozilla/Unused.h"
+#include "mozilla/IMEStateManager.h"
+#include "mozilla/VsyncDispatcher.h"
+#include "mozilla/layers/IAPZCTreeManager.h"
+#include "mozilla/layers/APZEventState.h"
+#include "mozilla/layers/APZThreadUtils.h"
+#include "mozilla/layers/ChromeProcessController.h"
+#include "mozilla/layers/InputAPZContext.h"
+#include "mozilla/layers/APZCCallbackHelper.h"
+#include "mozilla/dom/ContentChild.h"
+#include "mozilla/dom/TabParent.h"
+#include "mozilla/gfx/GPUProcessManager.h"
+#include "mozilla/Move.h"
+#include "mozilla/Services.h"
+#include "mozilla/Sprintf.h"
+#include "nsRefPtrHashtable.h"
+#include "TouchEvents.h"
+#include "WritingModes.h"
+#include "InputData.h"
+#include "FrameLayerBuilder.h"
+#ifdef ACCESSIBILITY
+#include "nsAccessibilityService.h"
+#endif
+#include "gfxConfig.h"
+#include "mozilla/layers/CompositorSession.h"
+#include "VRManagerChild.h"
+
+#ifdef DEBUG
+#include "nsIObserver.h"
+
+static void debug_RegisterPrefCallbacks();
+
+#endif
+
+#ifdef NOISY_WIDGET_LEAKS
+static int32_t gNumWidgets;
+#endif
+
+#ifdef XP_MACOSX
+#include "nsCocoaFeatures.h"
+#endif
+
+#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+static nsRefPtrHashtable<nsVoidPtrHashKey, nsIWidget>* sPluginWidgetList;
+#endif
+
+nsIRollupListener* nsBaseWidget::gRollupListener = nullptr;
+
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+using namespace mozilla::ipc;
+using namespace mozilla::widget;
+using namespace mozilla;
+using base::Thread;
+
+nsIContent* nsBaseWidget::mLastRollup = nullptr;
+// Global user preference for disabling native theme. Used
+// in NativeWindowTheme.
+bool            gDisableNativeTheme               = false;
+
+// Async pump timer during injected long touch taps
+#define TOUCH_INJECT_PUMP_TIMER_MSEC 50
+#define TOUCH_INJECT_LONG_TAP_DEFAULT_MSEC 1500
+int32_t nsIWidget::sPointerIdCounter = 0;
+
+// Some statics from nsIWidget.h
+/*static*/ uint64_t AutoObserverNotifier::sObserverId = 0;
+/*static*/ nsDataHashtable<nsUint64HashKey, nsCOMPtr<nsIObserver>> AutoObserverNotifier::sSavedObservers;
+
+namespace mozilla {
+namespace widget {
+
+void
+IMENotification::SelectionChangeDataBase::SetWritingMode(
+                                        const WritingMode& aWritingMode)
+{
+  mWritingMode = aWritingMode.mWritingMode;
+}
+
+WritingMode
+IMENotification::SelectionChangeDataBase::GetWritingMode() const
+{
+  return WritingMode(mWritingMode);
+}
+
+} // namespace widget
+} // namespace mozilla
+
+nsAutoRollup::nsAutoRollup()
+{
+  // remember if mLastRollup was null, and only clear it upon destruction
+  // if so. This prevents recursive usage of nsAutoRollup from clearing
+  // mLastRollup when it shouldn't.
+  wasClear = !nsBaseWidget::mLastRollup;
+}
+
+nsAutoRollup::~nsAutoRollup()
+{
+  if (nsBaseWidget::mLastRollup && wasClear) {
+    NS_RELEASE(nsBaseWidget::mLastRollup);
+  }
+}
+
+NS_IMPL_ISUPPORTS(nsBaseWidget, nsIWidget, nsISupportsWeakReference)
+
+//-------------------------------------------------------------------------
+//
+// nsBaseWidget constructor
+//
+//-------------------------------------------------------------------------
+
+nsBaseWidget::nsBaseWidget()
+: mWidgetListener(nullptr)
+, mAttachedWidgetListener(nullptr)
+, mPreviouslyAttachedWidgetListener(nullptr)
+, mLayerManager(nullptr)
+, mCompositorVsyncDispatcher(nullptr)
+, mCursor(eCursor_standard)
+, mBorderStyle(eBorderStyle_none)
+, mBounds(0,0,0,0)
+, mOriginalBounds(nullptr)
+, mClipRectCount(0)
+, mSizeMode(nsSizeMode_Normal)
+, mPopupLevel(ePopupLevelTop)
+, mPopupType(ePopupTypeAny)
+, mCompositorWidgetDelegate(nullptr)
+, mUpdateCursor(true)
+, mUseAttachedEvents(false)
+, mIMEHasFocus(false)
+#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
+, mAccessibilityInUseFlag(false)
+#endif
+{
+#ifdef NOISY_WIDGET_LEAKS
+  gNumWidgets++;
+  printf("WIDGETS+ = %d\n", gNumWidgets);
+#endif
+
+#ifdef DEBUG
+  debug_RegisterPrefCallbacks();
+#endif
+
+#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+  if (!sPluginWidgetList) {
+    sPluginWidgetList = new nsRefPtrHashtable<nsVoidPtrHashKey, nsIWidget>();
+  }
+#endif
+  mShutdownObserver = new WidgetShutdownObserver(this);
+}
+
+NS_IMPL_ISUPPORTS(WidgetShutdownObserver, nsIObserver)
+
+WidgetShutdownObserver::WidgetShutdownObserver(nsBaseWidget* aWidget) :
+  mWidget(aWidget),
+  mRegistered(false)
+{
+  Register();
+}
+
+WidgetShutdownObserver::~WidgetShutdownObserver()
+{
+  // No need to call Unregister(), we can't be destroyed until nsBaseWidget
+  // gets torn down. The observer service and nsBaseWidget have a ref on us
+  // so nsBaseWidget has to call Unregister and then clear its ref.
+}
+
+NS_IMETHODIMP
+WidgetShutdownObserver::Observe(nsISupports *aSubject,
+                                const char *aTopic,
+                                const char16_t *aData)
+{
+  if (mWidget && !strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID)) {
+    RefPtr<nsBaseWidget> widget(mWidget);
+    widget->Shutdown();
+  }
+  return NS_OK;
+}
+
+void
+WidgetShutdownObserver::Register()
+{
+  if (!mRegistered) {
+    mRegistered = true;
+    nsContentUtils::RegisterShutdownObserver(this);
+  }
+}
+
+void
+WidgetShutdownObserver::Unregister()
+{
+  if (mRegistered) {
+    mWidget = nullptr;
+    nsContentUtils::UnregisterShutdownObserver(this);
+    mRegistered = false;
+  }
+}
+
+void
+nsBaseWidget::Shutdown()
+{
+  RevokeTransactionIdAllocator();
+  DestroyCompositor();
+  FreeShutdownObserver();
+#if defined(XP_WIN) || defined(MOZ_WIDGET_GTK)
+  if (sPluginWidgetList) {
+    delete sPluginWidgetList;
+    sPluginWidgetList = nullptr;
+  }
+#endif
+}
+
+void nsBaseWidget::DestroyCompositor()
+{
+  // We release this before releasing the compositor, since it may hold the
+  // last reference to our ClientLayerManager. ClientLayerManager's dtor can
+  // trigger a paint, creating a new compositor, and we don't want to re-use
+  // the old vsync dispatcher.
+  if (mCompositorVsyncDispatcher) {
+    mCompositorVsyncDispatcher->Shutdown();
+    mCompositorVsyncDispatcher = nullptr;
+  }
+
+  // The compositor shutdown sequence looks like this:
+  //  1. CompositorSession calls CompositorBridgeChild::Destroy.
+  //  2. CompositorBridgeChild synchronously sends WillClose.
+  //  3. CompositorBridgeParent releases some resources (such as the layer
+  //     manager, compositor, and widget).
+  //  4. CompositorBridgeChild::Destroy returns.
+  //  5. Asynchronously, CompositorBridgeParent::ActorDestroy will fire on the
+  //     compositor thread when the I/O thread closes the IPC channel.
+  //  6. Step 5 will schedule DeferredDestroy on the compositor thread, which
+  //     releases the reference CompositorBridgeParent holds to itself.
+  //
+  // When CompositorSession::Shutdown returns, we assume the compositor is gone
+  // or will be gone very soon.
+  if (mCompositorSession) {
+    ReleaseContentController();
+    mAPZC = nullptr;
+    mCompositorWidgetDelegate = nullptr;
+    mCompositorBridgeChild = nullptr;
+
+    // XXX CompositorBridgeChild and CompositorBridgeParent might be re-created in
+    // ClientLayerManager destructor. See bug 1133426.
+    RefPtr<CompositorSession> session = mCompositorSession.forget();
+    session->Shutdown();
+  }
+}
+
+// This prevents the layer manager from starting a new transaction during
+// shutdown.
+void
+nsBaseWidget::RevokeTransactionIdAllocator()
+{
+  if (!mLayerManager) {
+    return;
+  }
+
+  ClientLayerManager* clm = mLayerManager->AsClientLayerManager();
+  if (!clm) {
+    return;
+  }
+
+  clm->SetTransactionIdAllocator(nullptr);
+}
+
+void nsBaseWidget::ReleaseContentController()
+{
+  if (mRootContentController) {
+    mRootContentController->Destroy();
+    mRootContentController = nullptr;
+  }
+}
+
+void nsBaseWidget::DestroyLayerManager()
+{
+  if (mLayerManager) {
+    mLayerManager->Destroy();
+    mLayerManager = nullptr;
+  }
+  DestroyCompositor();
+}
+
+void
+nsBaseWidget::OnRenderingDeviceReset()
+{
+  if (!mLayerManager || !mCompositorSession) {
+    return;
+  }
+
+  nsTArray<LayersBackend> backendHints;
+  gfxPlatform::GetPlatform()->GetCompositorBackends(ComputeShouldAccelerate(), backendHints);
+
+  // If the existing compositor does not use acceleration, and this widget
+  // should not be accelerated, then there's no point in resetting.
+  //
+  // Note that if this widget should be accelerated, but instead has a basic
+  // compositor, we still reset just in case we're now in the position to get
+  // accelerated layers again.
+  RefPtr<ClientLayerManager> clm = mLayerManager->AsClientLayerManager();
+  if (!ComputeShouldAccelerate() &&
+      clm->GetTextureFactoryIdentifier().mParentBackend != LayersBackend::LAYERS_BASIC)
+  {
+    return;
+  }
+
+  // Recreate the compositor.
+  TextureFactoryIdentifier identifier;
+  if (!mCompositorSession->Reset(backendHints, &identifier)) {
+    // No action was taken, so we don't have to do anything.
+    return;
+  }
+
+  // Invalidate all layers.
+  FrameLayerBuilder::InvalidateAllLayers(mLayerManager);
+
+  // Update the texture factory identifier.
+  clm->UpdateTextureFactoryIdentifier(identifier);
+  ImageBridgeChild::IdentifyCompositorTextureHost(identifier);
+  gfx::VRManagerChild::IdentifyTextureHost(identifier);
+}
+
+void
+nsBaseWidget::FreeShutdownObserver()
+{
+  if (mShutdownObserver) {
+    mShutdownObserver->Unregister();
+  }
+  mShutdownObserver = nullptr;
+}
+
+//-------------------------------------------------------------------------
+//
+// nsBaseWidget destructor
+//
+//-------------------------------------------------------------------------
+
+nsBaseWidget::~nsBaseWidget()
+{
+  IMEStateManager::WidgetDestroyed(this);
+
+  if (mLayerManager) {
+    if (BasicLayerManager* mgr = mLayerManager->AsBasicLayerManager()) {
+      mgr->ClearRetainerWidget();
+    }
+  }
+
+  FreeShutdownObserver();
+  RevokeTransactionIdAllocator();
+  DestroyLayerManager();
+
+#ifdef NOISY_WIDGET_LEAKS
+  gNumWidgets--;
+  printf("WIDGETS- = %d\n", gNumWidgets);
+#endif
+
+  delete mOriginalBounds;
+}
+
+//-------------------------------------------------------------------------
+//
+// Basic create.
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::BaseCreate(nsIWidget* aParent,
+                              nsWidgetInitData* aInitData)
+{
+  static bool gDisableNativeThemeCached = false;
+  if (!gDisableNativeThemeCached) {
+    Preferences::AddBoolVarCache(&gDisableNativeTheme,
+                                 "mozilla.widget.disable-native-theme",
+                                 gDisableNativeTheme);
+    gDisableNativeThemeCached = true;
+  }
+
+  // keep a reference to the device context
+  if (nullptr != aInitData) {
+    mWindowType = aInitData->mWindowType;
+    mBorderStyle = aInitData->mBorderStyle;
+    mPopupLevel = aInitData->mPopupLevel;
+    mPopupType = aInitData->mPopupHint;
+  }
+
+  if (aParent) {
+    aParent->AddChild(this);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Accessor functions to get/set the client data
+//
+//-------------------------------------------------------------------------
+
+nsIWidgetListener* nsBaseWidget::GetWidgetListener()
+{
+  return mWidgetListener;
+}
+
+void nsBaseWidget::SetWidgetListener(nsIWidgetListener* aWidgetListener)
+{
+  mWidgetListener = aWidgetListener;
+}
+
+already_AddRefed<nsIWidget>
+nsBaseWidget::CreateChild(const LayoutDeviceIntRect& aRect,
+                          nsWidgetInitData* aInitData,
+                          bool aForceUseIWidgetParent)
+{
+  nsIWidget* parent = this;
+  nsNativeWidget nativeParent = nullptr;
+
+  if (!aForceUseIWidgetParent) {
+    // Use only either parent or nativeParent, not both, to match
+    // existing code.  Eventually Create() should be divested of its
+    // nativeWidget parameter.
+    nativeParent = parent ? parent->GetNativeData(NS_NATIVE_WIDGET) : nullptr;
+    parent = nativeParent ? nullptr : parent;
+    MOZ_ASSERT(!parent || !nativeParent, "messed up logic");
+  }
+
+  nsCOMPtr<nsIWidget> widget;
+  if (aInitData && aInitData->mWindowType == eWindowType_popup) {
+    widget = AllocateChildPopupWidget();
+  } else {
+    static NS_DEFINE_IID(kCChildCID, NS_CHILD_CID);
+    widget = do_CreateInstance(kCChildCID);
+  }
+
+  if (widget &&
+      NS_SUCCEEDED(widget->Create(parent, nativeParent, aRect, aInitData))) {
+    return widget.forget();
+  }
+
+  return nullptr;
+}
+
+// Attach a view to our widget which we'll send events to.
+void
+nsBaseWidget::AttachViewToTopLevel(bool aUseAttachedEvents)
+{
+  NS_ASSERTION((mWindowType == eWindowType_toplevel ||
+                mWindowType == eWindowType_dialog ||
+                mWindowType == eWindowType_invisible ||
+                mWindowType == eWindowType_child),
+               "Can't attach to window of that type");
+
+  mUseAttachedEvents = aUseAttachedEvents;
+}
+
+nsIWidgetListener* nsBaseWidget::GetAttachedWidgetListener()
+ {
+   return mAttachedWidgetListener;
+ }
+
+nsIWidgetListener* nsBaseWidget::GetPreviouslyAttachedWidgetListener()
+ {
+   return mPreviouslyAttachedWidgetListener;
+ }
+
+void nsBaseWidget::SetPreviouslyAttachedWidgetListener(nsIWidgetListener* aListener)
+ {
+   mPreviouslyAttachedWidgetListener = aListener;
+ }
+
+void nsBaseWidget::SetAttachedWidgetListener(nsIWidgetListener* aListener)
+ {
+   mAttachedWidgetListener = aListener;
+ }
+
+//-------------------------------------------------------------------------
+//
+// Close this nsBaseWidget
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::Destroy()
+{
+  // Just in case our parent is the only ref to us
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+  // disconnect from the parent
+  nsIWidget *parent = GetParent();
+  if (parent) {
+    parent->RemoveChild(this);
+  }
+
+#if defined(XP_WIN)
+  // Allow our scroll capture container to be cleaned up, if we have one.
+  mScrollCaptureContainer = nullptr;
+#endif
+}
+
+
+//-------------------------------------------------------------------------
+//
+// Set this nsBaseWidget's parent
+//
+//-------------------------------------------------------------------------
+NS_IMETHODIMP nsBaseWidget::SetParent(nsIWidget* aNewParent)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget parent
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetParent(void)
+{
+  return nullptr;
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget top level widget
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetTopLevelWidget()
+{
+  nsIWidget *topLevelWidget = nullptr, *widget = this;
+  while (widget) {
+    topLevelWidget = widget;
+    widget = widget->GetParent();
+  }
+  return topLevelWidget;
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this nsBaseWidget's top (non-sheet) parent (if it's a sheet)
+//
+//-------------------------------------------------------------------------
+nsIWidget* nsBaseWidget::GetSheetWindowParent(void)
+{
+  return nullptr;
+}
+
+float nsBaseWidget::GetDPI()
+{
+  return 96.0f;
+}
+
+CSSToLayoutDeviceScale nsIWidget::GetDefaultScale()
+{
+  double devPixelsPerCSSPixel = DefaultScaleOverride();
+
+  if (devPixelsPerCSSPixel <= 0.0) {
+    devPixelsPerCSSPixel = GetDefaultScaleInternal();
+  }
+
+  return CSSToLayoutDeviceScale(devPixelsPerCSSPixel);
+}
+
+/* static */
+double nsIWidget::DefaultScaleOverride()
+{
+  // The number of device pixels per CSS pixel. A value <= 0 means choose
+  // automatically based on the DPI. A positive value is used as-is. This effectively
+  // controls the size of a CSS "px".
+  double devPixelsPerCSSPixel = -1.0;
+
+  nsAdoptingCString prefString = Preferences::GetCString("layout.css.devPixelsPerPx");
+  if (!prefString.IsEmpty()) {
+    devPixelsPerCSSPixel = PR_strtod(prefString, nullptr);
+  }
+
+  return devPixelsPerCSSPixel;
+}
+
+//-------------------------------------------------------------------------
+//
+// Add a child to the list of children
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::AddChild(nsIWidget* aChild)
+{
+  MOZ_ASSERT(!aChild->GetNextSibling() && !aChild->GetPrevSibling(),
+             "aChild not properly removed from its old child list");
+
+  if (!mFirstChild) {
+    mFirstChild = mLastChild = aChild;
+  } else {
+    // append to the list
+    MOZ_ASSERT(mLastChild);
+    MOZ_ASSERT(!mLastChild->GetNextSibling());
+    mLastChild->SetNextSibling(aChild);
+    aChild->SetPrevSibling(mLastChild);
+    mLastChild = aChild;
+  }
+}
+
+
+//-------------------------------------------------------------------------
+//
+// Remove a child from the list of children
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::RemoveChild(nsIWidget* aChild)
+{
+#ifdef DEBUG
+#ifdef XP_MACOSX
+  // nsCocoaWindow doesn't implement GetParent, so in that case parent will be
+  // null and we'll just have to do without this assertion.
+  nsIWidget* parent = aChild->GetParent();
+  NS_ASSERTION(!parent || parent == this, "Not one of our kids!");
+#else
+  MOZ_RELEASE_ASSERT(aChild->GetParent() == this, "Not one of our kids!");
+#endif
+#endif
+
+  if (mLastChild == aChild) {
+    mLastChild = mLastChild->GetPrevSibling();
+  }
+  if (mFirstChild == aChild) {
+    mFirstChild = mFirstChild->GetNextSibling();
+  }
+
+  // Now remove from the list.  Make sure that we pass ownership of the tail
+  // of the list correctly before we have aChild let go of it.
+  nsIWidget* prev = aChild->GetPrevSibling();
+  nsIWidget* next = aChild->GetNextSibling();
+  if (prev) {
+    prev->SetNextSibling(next);
+  }
+  if (next) {
+    next->SetPrevSibling(prev);
+  }
+
+  aChild->SetNextSibling(nullptr);
+  aChild->SetPrevSibling(nullptr);
+}
+
+
+//-------------------------------------------------------------------------
+//
+// Sets widget's position within its parent's child list.
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::SetZIndex(int32_t aZIndex)
+{
+  // Hold a ref to ourselves just in case, since we're going to remove
+  // from our parent.
+  nsCOMPtr<nsIWidget> kungFuDeathGrip(this);
+
+  mZIndex = aZIndex;
+
+  // reorder this child in its parent's list.
+  nsBaseWidget* parent = static_cast<nsBaseWidget*>(GetParent());
+  if (parent) {
+    parent->RemoveChild(this);
+    // Scope sib outside the for loop so we can check it afterward
+    nsIWidget* sib = parent->GetFirstChild();
+    for ( ; sib; sib = sib->GetNextSibling()) {
+      int32_t childZIndex = GetZIndex();
+      if (aZIndex < childZIndex) {
+        // Insert ourselves before sib
+        nsIWidget* prev = sib->GetPrevSibling();
+        mNextSibling = sib;
+        mPrevSibling = prev;
+        sib->SetPrevSibling(this);
+        if (prev) {
+          prev->SetNextSibling(this);
+        } else {
+          NS_ASSERTION(sib == parent->mFirstChild, "Broken child list");
+          // We've taken ownership of sib, so it's safe to have parent let
+          // go of it
+          parent->mFirstChild = this;
+        }
+        PlaceBehind(eZPlacementBelow, sib, false);
+        break;
+      }
+    }
+    // were we added to the list?
+    if (!sib) {
+      parent->AddChild(this);
+    }
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Maximize, minimize or restore the window. The BaseWidget implementation
+// merely stores the state.
+//
+//-------------------------------------------------------------------------
+void
+nsBaseWidget::SetSizeMode(nsSizeMode aMode)
+{
+  MOZ_ASSERT(aMode == nsSizeMode_Normal ||
+             aMode == nsSizeMode_Minimized ||
+             aMode == nsSizeMode_Maximized ||
+             aMode == nsSizeMode_Fullscreen);
+  mSizeMode = aMode;
+}
+
+//-------------------------------------------------------------------------
+//
+// Get this component cursor
+//
+//-------------------------------------------------------------------------
+nsCursor nsBaseWidget::GetCursor()
+{
+  return mCursor;
+}
+
+NS_IMETHODIMP nsBaseWidget::SetCursor(nsCursor aCursor)
+{
+  mCursor = aCursor;
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsBaseWidget::SetCursor(imgIContainer* aCursor,
+                                      uint32_t aHotspotX, uint32_t aHotspotY)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+//-------------------------------------------------------------------------
+//
+// Window transparency methods
+//
+//-------------------------------------------------------------------------
+
+void nsBaseWidget::SetTransparencyMode(nsTransparencyMode aMode) {
+}
+
+nsTransparencyMode nsBaseWidget::GetTransparencyMode() {
+  return eTransparencyOpaque;
+}
+
+bool
+nsBaseWidget::IsWindowClipRegionEqual(const nsTArray<LayoutDeviceIntRect>& aRects)
+{
+  return mClipRects &&
+         mClipRectCount == aRects.Length() &&
+         memcmp(mClipRects.get(), aRects.Elements(), sizeof(LayoutDeviceIntRect)*mClipRectCount) == 0;
+}
+
+void
+nsBaseWidget::StoreWindowClipRegion(const nsTArray<LayoutDeviceIntRect>& aRects)
+{
+  mClipRectCount = aRects.Length();
+  mClipRects = MakeUnique<LayoutDeviceIntRect[]>(mClipRectCount);
+  if (mClipRects) {
+    memcpy(mClipRects.get(), aRects.Elements(), sizeof(LayoutDeviceIntRect)*mClipRectCount);
+  }
+}
+
+void
+nsBaseWidget::GetWindowClipRegion(nsTArray<LayoutDeviceIntRect>* aRects)
+{
+  if (mClipRects) {
+    aRects->AppendElements(mClipRects.get(), mClipRectCount);
+  } else {
+    aRects->AppendElement(LayoutDeviceIntRect(0, 0, mBounds.width, mBounds.height));
+  }
+}
+
+const LayoutDeviceIntRegion
+nsBaseWidget::RegionFromArray(const nsTArray<LayoutDeviceIntRect>& aRects)
+{
+  LayoutDeviceIntRegion region;
+  for (uint32_t i = 0; i < aRects.Length(); ++i) {
+    region.Or(region, aRects[i]);
+  }
+  return region;
+}
+
+void
+nsBaseWidget::ArrayFromRegion(const LayoutDeviceIntRegion& aRegion,
+                              nsTArray<LayoutDeviceIntRect>& aRects)
+{
+  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
+    aRects.AppendElement(iter.Get());
+  }
+}
+
+nsresult
+nsBaseWidget::SetWindowClipRegion(const nsTArray<LayoutDeviceIntRect>& aRects,
+                                  bool aIntersectWithExisting)
+{
+  if (!aIntersectWithExisting) {
+    StoreWindowClipRegion(aRects);
+  } else {
+    // get current rects
+    nsTArray<LayoutDeviceIntRect> currentRects;
+    GetWindowClipRegion(&currentRects);
+    // create region from them
+    LayoutDeviceIntRegion currentRegion = RegionFromArray(currentRects);
+    // create region from new rects
+    LayoutDeviceIntRegion newRegion = RegionFromArray(aRects);
+    // intersect regions
+    LayoutDeviceIntRegion intersection;
+    intersection.And(currentRegion, newRegion);
+    // create int rect array from intersection
+    nsTArray<LayoutDeviceIntRect> rects;
+    ArrayFromRegion(intersection, rects);
+    // store
+    StoreWindowClipRegion(rects);
+  }
+  return NS_OK;
+}
+
+//-------------------------------------------------------------------------
+//
+// Hide window borders/decorations for this widget
+//
+//-------------------------------------------------------------------------
+NS_IMETHODIMP nsBaseWidget::HideWindowChrome(bool aShouldHide)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+/* virtual */ void
+nsBaseWidget::PerformFullscreenTransition(FullscreenTransitionStage aStage,
+                                          uint16_t aDuration,
+                                          nsISupports* aData,
+                                          nsIRunnable* aCallback)
+{
+  MOZ_ASSERT_UNREACHABLE(
+    "Should never call PerformFullscreenTransition on nsBaseWidget");
+}
+
+//-------------------------------------------------------------------------
+//
+// Put the window into full-screen mode
+//
+//-------------------------------------------------------------------------
+void
+nsBaseWidget::InfallibleMakeFullScreen(bool aFullScreen, nsIScreen* aScreen)
+{
+  HideWindowChrome(aFullScreen);
+
+  if (aFullScreen) {
+    if (!mOriginalBounds) {
+      mOriginalBounds = new LayoutDeviceIntRect();
+    }
+    *mOriginalBounds = GetScreenBounds();
+
+    // Move to top-left corner of screen and size to the screen dimensions
+    nsCOMPtr<nsIScreen> screen = aScreen;
+    if (!screen) {
+      screen = GetWidgetScreen();
+    }
+    if (screen) {
+      int32_t left, top, width, height;
+      if (NS_SUCCEEDED(screen->GetRectDisplayPix(&left, &top, &width, &height))) {
+        Resize(left, top, width, height, true);
+      }
+    }
+  } else if (mOriginalBounds) {
+    if (BoundsUseDesktopPixels()) {
+      DesktopRect deskRect = *mOriginalBounds / GetDesktopToDeviceScale();
+      Resize(deskRect.x, deskRect.y, deskRect.width, deskRect.height, true);
+    } else {
+      Resize(mOriginalBounds->x, mOriginalBounds->y, mOriginalBounds->width,
+             mOriginalBounds->height, true);
+    }
+  }
+}
+
+nsresult
+nsBaseWidget::MakeFullScreen(bool aFullScreen, nsIScreen* aScreen)
+{
+  InfallibleMakeFullScreen(aFullScreen, aScreen);
+  return NS_OK;
+}
+
+nsBaseWidget::AutoLayerManagerSetup::AutoLayerManagerSetup(
+    nsBaseWidget* aWidget, gfxContext* aTarget,
+    BufferMode aDoubleBuffering, ScreenRotation aRotation)
+  : mWidget(aWidget)
+{
+  LayerManager* lm = mWidget->GetLayerManager();
+  NS_ASSERTION(!lm || lm->GetBackendType() == LayersBackend::LAYERS_BASIC,
+    "AutoLayerManagerSetup instantiated for non-basic layer backend!");
+  if (lm) {
+    mLayerManager = lm->AsBasicLayerManager();
+    if (mLayerManager) {
+      mLayerManager->SetDefaultTarget(aTarget);
+      mLayerManager->SetDefaultTargetConfiguration(aDoubleBuffering, aRotation);
+    }
+  }
+}
+
+nsBaseWidget::AutoLayerManagerSetup::~AutoLayerManagerSetup()
+{
+  if (mLayerManager) {
+    mLayerManager->SetDefaultTarget(nullptr);
+    mLayerManager->SetDefaultTargetConfiguration(mozilla::layers::BufferMode::BUFFER_NONE, ROTATION_0);
+  }
+}
+
+bool nsBaseWidget::IsSmallPopup() const
+{
+  return mWindowType == eWindowType_popup && mPopupType != ePopupTypePanel;
+}
+
+bool
+nsBaseWidget::ComputeShouldAccelerate()
+{
+  return gfx::gfxConfig::IsEnabled(gfx::Feature::HW_COMPOSITING) &&
+         WidgetTypeSupportsAcceleration();
+}
+
+bool
+nsBaseWidget::UseAPZ()
+{
+  return (gfxPlatform::AsyncPanZoomEnabled() &&
+          (WindowType() == eWindowType_toplevel || WindowType() == eWindowType_child));
+}
+
+void nsBaseWidget::CreateCompositor()
+{
+  LayoutDeviceIntRect rect = GetBounds();
+  CreateCompositor(rect.width, rect.height);
+}
+
+already_AddRefed<GeckoContentController>
+nsBaseWidget::CreateRootContentController()
+{
+  RefPtr<GeckoContentController> controller = new ChromeProcessController(this, mAPZEventState, mAPZC);
+  return controller.forget();
+}
+
+void nsBaseWidget::ConfigureAPZCTreeManager()
+{
+  MOZ_ASSERT(mAPZC);
+
+  ConfigureAPZControllerThread();
+
+  mAPZC->SetDPI(GetDPI());
+
+  RefPtr<IAPZCTreeManager> treeManager = mAPZC;  // for capture by the lambdas
+
+  ContentReceivedInputBlockCallback callback(
+      [treeManager](const ScrollableLayerGuid& aGuid,
+                    uint64_t aInputBlockId,
+                    bool aPreventDefault)
+      {
+        MOZ_ASSERT(NS_IsMainThread());
+        APZThreadUtils::RunOnControllerThread(NewRunnableMethod
+                                              <uint64_t, bool>(treeManager,
+                                                               &IAPZCTreeManager::ContentReceivedInputBlock,
+                                                               aInputBlockId,
+                                                               aPreventDefault));
+      });
+  mAPZEventState = new APZEventState(this, mozilla::Move(callback));
+
+  mSetAllowedTouchBehaviorCallback = [treeManager](uint64_t aInputBlockId,
+                                                   const nsTArray<TouchBehaviorFlags>& aFlags)
+  {
+    MOZ_ASSERT(NS_IsMainThread());
+    APZThreadUtils::RunOnControllerThread(NewRunnableMethod
+      <uint64_t,
+       StoreCopyPassByLRef<nsTArray<TouchBehaviorFlags>>>(treeManager,
+                                                          &IAPZCTreeManager::SetAllowedTouchBehavior,
+                                                          aInputBlockId, aFlags));
+  };
+
+  mRootContentController = CreateRootContentController();
+  if (mRootContentController) {
+    mCompositorSession->SetContentController(mRootContentController);
+  }
+
+  // When APZ is enabled, we can actually enable raw touch events because we
+  // have code that can deal with them properly. If APZ is not enabled, this
+  // function doesn't get called.
+  if (Preferences::GetInt("dom.w3c_touch_events.enabled", 0) ||
+      Preferences::GetBool("dom.w3c_pointer_events.enabled", false)) {
+    RegisterTouchWindow();
+  }
+}
+
+void nsBaseWidget::ConfigureAPZControllerThread()
+{
+  // By default the controller thread is the main thread.
+  APZThreadUtils::SetControllerThread(MessageLoop::current());
+}
+
+void
+nsBaseWidget::SetConfirmedTargetAPZC(uint64_t aInputBlockId,
+                                     const nsTArray<ScrollableLayerGuid>& aTargets) const
+{
+  APZThreadUtils::RunOnControllerThread(NewRunnableMethod
+    <uint64_t, StoreCopyPassByRRef<nsTArray<ScrollableLayerGuid>>>(mAPZC,
+                                                                   &IAPZCTreeManager::SetTargetAPZC,
+                                                                   aInputBlockId, aTargets));
+}
+
+void
+nsBaseWidget::UpdateZoomConstraints(const uint32_t& aPresShellId,
+                                    const FrameMetrics::ViewID& aViewId,
+                                    const Maybe<ZoomConstraints>& aConstraints)
+{
+  if (!mCompositorSession || !mAPZC) {
+    if (mInitialZoomConstraints) {
+      MOZ_ASSERT(mInitialZoomConstraints->mPresShellID == aPresShellId);
+      MOZ_ASSERT(mInitialZoomConstraints->mViewID == aViewId);
+      if (!aConstraints) {
+        mInitialZoomConstraints.reset();
+      }
+    }
+
+    if (aConstraints) {
+      // We have some constraints, but the compositor and APZC aren't created yet.
+      // Save these so we can use them later.
+      mInitialZoomConstraints = Some(InitialZoomConstraints(aPresShellId, aViewId, aConstraints.ref()));
+    }
+    return;
+  }
+  uint64_t layersId = mCompositorSession->RootLayerTreeId();
+  mAPZC->UpdateZoomConstraints(ScrollableLayerGuid(layersId, aPresShellId, aViewId),
+                               aConstraints);
+}
+
+bool
+nsBaseWidget::AsyncPanZoomEnabled() const
+{
+  return !!mAPZC;
+}
+
+nsEventStatus
+nsBaseWidget::ProcessUntransformedAPZEvent(WidgetInputEvent* aEvent,
+                                           const ScrollableLayerGuid& aGuid,
+                                           uint64_t aInputBlockId,
+                                           nsEventStatus aApzResponse)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  InputAPZContext context(aGuid, aInputBlockId, aApzResponse);
+
+  // If this is an event that the APZ has targeted to an APZC in the root
+  // process, apply that APZC's callback-transform before dispatching the
+  // event. If the event is instead targeted to an APZC in the child process,
+  // the transform will be applied in the child process before dispatching
+  // the event there (see e.g. TabChild::RecvRealTouchEvent()).
+  if (aGuid.mLayersId == mCompositorSession->RootLayerTreeId()) {
+    APZCCallbackHelper::ApplyCallbackTransform(*aEvent, aGuid,
+        GetDefaultScale());
+  }
+
+  // Make a copy of the original event for the APZCCallbackHelper helpers that
+  // we call later, because the event passed to DispatchEvent can get mutated in
+  // ways that we don't want (i.e. touch points can get stripped out).
+  nsEventStatus status;
+  UniquePtr<WidgetEvent> original(aEvent->Duplicate());
+  DispatchEvent(aEvent, status);
+
+  if (mAPZC && !context.WasRoutedToChildProcess() && aInputBlockId) {
+    // EventStateManager did not route the event into the child process.
+    // It's safe to communicate to APZ that the event has been processed.
+    // TODO: Eventually we'll be able to move the SendSetTargetAPZCNotification
+    // call into APZEventState::Process*Event() as well.
+    if (WidgetTouchEvent* touchEvent = aEvent->AsTouchEvent()) {
+      if (touchEvent->mMessage == eTouchStart) {
+        if (gfxPrefs::TouchActionEnabled()) {
+          APZCCallbackHelper::SendSetAllowedTouchBehaviorNotification(this,
+              GetDocument(), *(original->AsTouchEvent()), aInputBlockId,
+              mSetAllowedTouchBehaviorCallback);
+        }
+        APZCCallbackHelper::SendSetTargetAPZCNotification(this, GetDocument(),
+            *(original->AsTouchEvent()), aGuid, aInputBlockId);
+      }
+      mAPZEventState->ProcessTouchEvent(*touchEvent, aGuid, aInputBlockId,
+          aApzResponse, status);
+    } else if (WidgetWheelEvent* wheelEvent = aEvent->AsWheelEvent()) {
+      MOZ_ASSERT(wheelEvent->mFlags.mHandledByAPZ);
+      APZCCallbackHelper::SendSetTargetAPZCNotification(this, GetDocument(),
+          *(original->AsWheelEvent()), aGuid, aInputBlockId);
+      if (wheelEvent->mCanTriggerSwipe) {
+        ReportSwipeStarted(aInputBlockId, wheelEvent->TriggersSwipe());
+      }
+      mAPZEventState->ProcessWheelEvent(*wheelEvent, aGuid, aInputBlockId);
+    } else if (WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent()) {
+      MOZ_ASSERT(mouseEvent->mFlags.mHandledByAPZ);
+      APZCCallbackHelper::SendSetTargetAPZCNotification(this, GetDocument(),
+          *(original->AsMouseEvent()), aGuid, aInputBlockId);
+      mAPZEventState->ProcessMouseEvent(*mouseEvent, aGuid, aInputBlockId);
+    }
+  }
+
+  return status;
+}
+
+class DispatchWheelEventOnMainThread : public Runnable
+{
+public:
+  DispatchWheelEventOnMainThread(const ScrollWheelInput& aWheelInput,
+                                 nsBaseWidget* aWidget,
+                                 nsEventStatus aAPZResult,
+                                 uint64_t aInputBlockId,
+                                 ScrollableLayerGuid aGuid)
+    : mWheelInput(aWheelInput)
+    , mWidget(aWidget)
+    , mAPZResult(aAPZResult)
+    , mInputBlockId(aInputBlockId)
+    , mGuid(aGuid)
+  {
+  }
+
+  NS_IMETHOD Run() override
+  {
+    WidgetWheelEvent wheelEvent = mWheelInput.ToWidgetWheelEvent(mWidget);
+    mWidget->ProcessUntransformedAPZEvent(&wheelEvent, mGuid, mInputBlockId, mAPZResult);
+    return NS_OK;
+  }
+
+private:
+  ScrollWheelInput mWheelInput;
+  nsBaseWidget* mWidget;
+  nsEventStatus mAPZResult;
+  uint64_t mInputBlockId;
+  ScrollableLayerGuid mGuid;
+};
+
+class DispatchWheelInputOnControllerThread : public Runnable
+{
+public:
+  DispatchWheelInputOnControllerThread(const WidgetWheelEvent& aWheelEvent,
+                                       IAPZCTreeManager* aAPZC,
+                                       nsBaseWidget* aWidget)
+    : mMainMessageLoop(MessageLoop::current())
+    , mWheelInput(aWheelEvent)
+    , mAPZC(aAPZC)
+    , mWidget(aWidget)
+    , mInputBlockId(0)
+  {
+  }
+
+  NS_IMETHOD Run() override
+  {
+    nsEventStatus result = mAPZC->ReceiveInputEvent(mWheelInput, &mGuid, &mInputBlockId);
+    if (result == nsEventStatus_eConsumeNoDefault) {
+      return NS_OK;
+    }
+    RefPtr<Runnable> r = new DispatchWheelEventOnMainThread(mWheelInput, mWidget, result, mInputBlockId, mGuid);
+    mMainMessageLoop->PostTask(r.forget());
+    return NS_OK;
+  }
+
+private:
+  MessageLoop* mMainMessageLoop;
+  ScrollWheelInput mWheelInput;
+  RefPtr<IAPZCTreeManager> mAPZC;
+  nsBaseWidget* mWidget;
+  uint64_t mInputBlockId;
+  ScrollableLayerGuid mGuid;
+};
+
+void
+nsBaseWidget::DispatchTouchInput(MultiTouchInput& aInput)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+    uint64_t inputBlockId = 0;
+    ScrollableLayerGuid guid;
+
+    nsEventStatus result = mAPZC->ReceiveInputEvent(aInput, &guid, &inputBlockId);
+    if (result == nsEventStatus_eConsumeNoDefault) {
+      return;
+    }
+
+    WidgetTouchEvent event = aInput.ToWidgetTouchEvent(this);
+    ProcessUntransformedAPZEvent(&event, guid, inputBlockId, result);
+  } else {
+    WidgetTouchEvent event = aInput.ToWidgetTouchEvent(this);
+
+    nsEventStatus status;
+    DispatchEvent(&event, status);
+  }
+}
+
+nsEventStatus
+nsBaseWidget::DispatchInputEvent(WidgetInputEvent* aEvent)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    if (APZThreadUtils::IsControllerThread()) {
+      uint64_t inputBlockId = 0;
+      ScrollableLayerGuid guid;
+
+      nsEventStatus result = mAPZC->ReceiveInputEvent(*aEvent, &guid, &inputBlockId);
+      if (result == nsEventStatus_eConsumeNoDefault) {
+          return result;
+      }
+      return ProcessUntransformedAPZEvent(aEvent, guid, inputBlockId, result);
+    } else {
+      WidgetWheelEvent* wheelEvent = aEvent->AsWheelEvent();
+      if (wheelEvent) {
+        RefPtr<Runnable> r = new DispatchWheelInputOnControllerThread(*wheelEvent, mAPZC, this);
+        APZThreadUtils::RunOnControllerThread(r.forget());
+        return nsEventStatus_eConsumeDoDefault;
+      }
+      MOZ_CRASH();
+    }
+  }
+
+  nsEventStatus status;
+  DispatchEvent(aEvent, status);
+  return status;
+}
+
+void
+nsBaseWidget::DispatchEventToAPZOnly(mozilla::WidgetInputEvent* aEvent)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mAPZC) {
+    MOZ_ASSERT(APZThreadUtils::IsControllerThread());
+    uint64_t inputBlockId = 0;
+    ScrollableLayerGuid guid;
+    mAPZC->ReceiveInputEvent(*aEvent, &guid, &inputBlockId);
+  }
+}
+
+nsIDocument*
+nsBaseWidget::GetDocument() const
+{
+  if (mWidgetListener) {
+    if (nsIPresShell* presShell = mWidgetListener->GetPresShell()) {
+      return presShell->GetDocument();
+    }
+  }
+  return nullptr;
+}
+
+void nsBaseWidget::CreateCompositorVsyncDispatcher()
+{
+  // Parent directly listens to the vsync source whereas
+  // child process communicate via IPC
+  // Should be called AFTER gfxPlatform is initialized
+  if (XRE_IsParentProcess()) {
+    mCompositorVsyncDispatcher = new CompositorVsyncDispatcher();
+  }
+}
+
+CompositorVsyncDispatcher*
+nsBaseWidget::GetCompositorVsyncDispatcher()
+{
+  return mCompositorVsyncDispatcher;
+}
+
+void nsBaseWidget::CreateCompositor(int aWidth, int aHeight)
+{
+  // This makes sure that gfxPlatforms gets initialized if it hasn't by now.
+  gfxPlatform::GetPlatform();
+
+  MOZ_ASSERT(gfxPlatform::UsesOffMainThreadCompositing(),
+             "This function assumes OMTC");
+
+  MOZ_ASSERT(!mCompositorSession && !mCompositorBridgeChild,
+    "Should have properly cleaned up the previous PCompositor pair beforehand");
+
+  if (mCompositorBridgeChild) {
+    mCompositorBridgeChild->Destroy();
+  }
+
+  // Recreating this is tricky, as we may still have an old and we need
+  // to make sure it's properly destroyed by calling DestroyCompositor!
+
+  // If we've already received a shutdown notification, don't try
+  // create a new compositor.
+  if (!mShutdownObserver) {
+    return;
+  }
+
+  CreateCompositorVsyncDispatcher();
+
+  RefPtr<ClientLayerManager> lm = new ClientLayerManager(this);
+
+  bool useAPZ = UseAPZ();
+
+  gfx::GPUProcessManager* gpu = gfx::GPUProcessManager::Get();
+  mCompositorSession = gpu->CreateTopLevelCompositor(
+    this,
+    lm,
+    GetDefaultScale(),
+    useAPZ,
+    UseExternalCompositingSurface(),
+    gfx::IntSize(aWidth, aHeight));
+  mCompositorBridgeChild = mCompositorSession->GetCompositorBridgeChild();
+  mCompositorWidgetDelegate = mCompositorSession->GetCompositorWidgetDelegate();
+
+  if (useAPZ) {
+    mAPZC = mCompositorSession->GetAPZCTreeManager();
+    ConfigureAPZCTreeManager();
+  } else {
+    mAPZC = nullptr;
+  }
+
+  if (mInitialZoomConstraints) {
+    UpdateZoomConstraints(mInitialZoomConstraints->mPresShellID,
+                          mInitialZoomConstraints->mViewID,
+                          Some(mInitialZoomConstraints->mConstraints));
+    mInitialZoomConstraints.reset();
+  }
+
+  ShadowLayerForwarder* lf = lm->AsShadowForwarder();
+  // As long as we are creating a ClientLayerManager above lf must be non-null.
+  MOZ_ASSERT(lf);
+
+  if (lf) {
+    TextureFactoryIdentifier textureFactoryIdentifier;
+    PLayerTransactionChild* shadowManager = nullptr;
+
+    nsTArray<LayersBackend> backendHints;
+    gfxPlatform::GetPlatform()->GetCompositorBackends(ComputeShouldAccelerate(), backendHints);
+
+    bool success = false;
+    if (!backendHints.IsEmpty()) {
+      shadowManager = mCompositorBridgeChild->SendPLayerTransactionConstructor(
+        backendHints, 0, &textureFactoryIdentifier, &success);
+    }
+
+    if (!success) {
+      NS_WARNING("Failed to create an OMT compositor.");
+      DestroyCompositor();
+      mLayerManager = nullptr;
+      return;
+    }
+
+    lf->SetShadowManager(shadowManager);
+    if (ClientLayerManager* clm = lm->AsClientLayerManager()) {
+      clm->UpdateTextureFactoryIdentifier(textureFactoryIdentifier);
+    }
+    // Some popup or transparent widgets may use a different backend than the
+    // compositors used with ImageBridge and VR (and more generally web content).
+    if (WidgetTypeSupportsAcceleration()) {
+      ImageBridgeChild::IdentifyCompositorTextureHost(textureFactoryIdentifier);
+      gfx::VRManagerChild::IdentifyTextureHost(textureFactoryIdentifier);
+    }
+  }
+
+  WindowUsesOMTC();
+
+  mLayerManager = lm.forget();
+
+  // Only track compositors for top-level windows, since other window types
+  // may use the basic compositor.  Except on the OS X - see bug 1306383
+#if defined(XP_MACOSX)
+  bool getCompositorFromThisWindow = true;
+#else
+  bool getCompositorFromThisWindow = (mWindowType == eWindowType_toplevel);
+#endif
+
+  if (getCompositorFromThisWindow) {
+    gfxPlatform::GetPlatform()->NotifyCompositorCreated(mLayerManager->GetCompositorBackendType());
+  }
+}
+
+void nsBaseWidget::NotifyRemoteCompositorSessionLost(CompositorSession* aSession)
+{
+  MOZ_ASSERT(aSession == mCompositorSession);
+  DestroyLayerManager();
+}
+
+bool nsBaseWidget::ShouldUseOffMainThreadCompositing()
+{
+  return gfxPlatform::UsesOffMainThreadCompositing();
+}
+
+LayerManager* nsBaseWidget::GetLayerManager(PLayerTransactionChild* aShadowManager,
+                                            LayersBackend aBackendHint,
+                                            LayerManagerPersistence aPersistence)
+{
+  if (!mLayerManager) {
+    if (!mShutdownObserver) {
+      // We are shutting down, do not try to re-create a LayerManager
+      return nullptr;
+    }
+    // Try to use an async compositor first, if possible
+    if (ShouldUseOffMainThreadCompositing()) {
+      // e10s uses the parameter to pass in the shadow manager from the TabChild
+      // so we don't expect to see it there since this doesn't support e10s.
+      NS_ASSERTION(aShadowManager == nullptr, "Async Compositor not supported with e10s");
+      CreateCompositor();
+    }
+
+    if (!mLayerManager) {
+      mLayerManager = CreateBasicLayerManager();
+    }
+  }
+  return mLayerManager;
+}
+
+LayerManager* nsBaseWidget::CreateBasicLayerManager()
+{
+  return new BasicLayerManager(this);
+}
+
+CompositorBridgeChild* nsBaseWidget::GetRemoteRenderer()
+{
+  return mCompositorBridgeChild;
+}
+
+already_AddRefed<gfx::DrawTarget>
+nsBaseWidget::StartRemoteDrawing()
+{
+  return nullptr;
+}
+
+uint32_t
+nsBaseWidget::GetGLFrameBufferFormat()
+{
+  return LOCAL_GL_RGBA;
+}
+
+//-------------------------------------------------------------------------
+//
+// Destroy the window
+//
+//-------------------------------------------------------------------------
+void nsBaseWidget::OnDestroy()
+{
+  if (mTextEventDispatcher) {
+    mTextEventDispatcher->OnDestroyWidget();
+    // Don't release it until this widget actually released because after this
+    // is called, TextEventDispatcher() may create it again.
+  }
+
+  // If this widget is being destroyed, let the APZ code know to drop references
+  // to this widget. Callers of this function all should be holding a deathgrip
+  // on this widget already.
+  ReleaseContentController();
+}
+
+NS_IMETHODIMP nsBaseWidget::MoveClient(double aX, double aY)
+{
+  LayoutDeviceIntPoint clientOffset(GetClientOffset());
+
+  // GetClientOffset returns device pixels; scale back to desktop pixels
+  // if that's what this widget uses for the Move/Resize APIs
+  if (BoundsUseDesktopPixels()) {
+    DesktopPoint desktopOffset = clientOffset / GetDesktopToDeviceScale();
+    return Move(aX - desktopOffset.x, aY - desktopOffset.y);
+  } else {
+    return Move(aX - clientOffset.x, aY - clientOffset.y);
+  }
+}
+
+NS_IMETHODIMP nsBaseWidget::ResizeClient(double aWidth,
+                                         double aHeight,
+                                         bool aRepaint)
+{
+  NS_ASSERTION((aWidth >=0) , "Negative width passed to ResizeClient");
+  NS_ASSERTION((aHeight >=0), "Negative height passed to ResizeClient");
+
+  LayoutDeviceIntRect clientBounds = GetClientBounds();
+
+  // GetClientBounds and mBounds are device pixels; scale back to desktop pixels
+  // if that's what this widget uses for the Move/Resize APIs
+  if (BoundsUseDesktopPixels()) {
+    DesktopSize desktopDelta =
+      (LayoutDeviceIntSize(mBounds.width, mBounds.height) -
+       clientBounds.Size()) / GetDesktopToDeviceScale();
+    return Resize(aWidth + desktopDelta.width, aHeight + desktopDelta.height,
+                  aRepaint);
+  } else {
+    return Resize(mBounds.width + (aWidth - clientBounds.width),
+                  mBounds.height + (aHeight - clientBounds.height), aRepaint);
+  }
+}
+
+NS_IMETHODIMP nsBaseWidget::ResizeClient(double aX,
+                                         double aY,
+                                         double aWidth,
+                                         double aHeight,
+                                         bool aRepaint)
+{
+  NS_ASSERTION((aWidth >=0) , "Negative width passed to ResizeClient");
+  NS_ASSERTION((aHeight >=0), "Negative height passed to ResizeClient");
+
+  LayoutDeviceIntRect clientBounds = GetClientBounds();
+  LayoutDeviceIntPoint clientOffset = GetClientOffset();
+
+  if (BoundsUseDesktopPixels()) {
+    DesktopToLayoutDeviceScale scale = GetDesktopToDeviceScale();
+    DesktopPoint desktopOffset = clientOffset / scale;
+    DesktopSize desktopDelta =
+      (LayoutDeviceIntSize(mBounds.width, mBounds.height) -
+       clientBounds.Size()) / scale;
+    return Resize(aX - desktopOffset.x, aY - desktopOffset.y,
+                  aWidth + desktopDelta.width, aHeight + desktopDelta.height,
+                  aRepaint);
+  } else {
+    return Resize(aX - clientOffset.x, aY - clientOffset.y,
+                  aWidth + mBounds.width - clientBounds.width,
+                  aHeight + mBounds.height - clientBounds.height,
+                  aRepaint);
+  }
+}
+
+//-------------------------------------------------------------------------
+//
+// Bounds
+//
+//-------------------------------------------------------------------------
+
+/**
+* If the implementation of nsWindow supports borders this method MUST be overridden
+*
+**/
+LayoutDeviceIntRect
+nsBaseWidget::GetClientBounds()
+{
+  return GetBounds();
+}
+
+/**
+* If the implementation of nsWindow supports borders this method MUST be overridden
+*
+**/
+LayoutDeviceIntRect
+nsBaseWidget::GetBounds()
+{
+  return mBounds;
+}
+
+/**
+* If the implementation of nsWindow uses a local coordinate system within the window,
+* this method must be overridden
+*
+**/
+LayoutDeviceIntRect
+nsBaseWidget::GetScreenBounds()
+{
+  return GetBounds();
+}
+
+nsresult
+nsBaseWidget::GetRestoredBounds(LayoutDeviceIntRect& aRect)
+{
+  if (SizeMode() != nsSizeMode_Normal) {
+    return NS_ERROR_FAILURE;
+  }
+  aRect = GetScreenBounds();
+  return NS_OK;
+}
+
+LayoutDeviceIntPoint
+nsBaseWidget::GetClientOffset()
+{
+  return LayoutDeviceIntPoint(0, 0);
+}
+
+NS_IMETHODIMP
+nsBaseWidget::SetNonClientMargins(LayoutDeviceIntMargin &margins)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+uint32_t nsBaseWidget::GetMaxTouchPoints() const
+{
+  return 0;
+}
+
+NS_IMETHODIMP
+nsBaseWidget::GetAttention(int32_t aCycleCount) {
+    return NS_OK;
+}
+
+bool
+nsBaseWidget::HasPendingInputEvent()
+{
+  return false;
+}
+
+NS_IMETHODIMP
+nsBaseWidget::SetIcon(const nsAString&)
+{
+  return NS_OK;
+}
+
+bool
+nsBaseWidget::ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect)
+{
+  return false;
+}
+
+/**
+ * Modifies aFile to point at an icon file with the given name and suffix.  The
+ * suffix may correspond to a file extension with leading '.' if appropriate.
+ * Returns true if the icon file exists and can be read.
+ */
+static bool
+ResolveIconNameHelper(nsIFile *aFile,
+                      const nsAString &aIconName,
+                      const nsAString &aIconSuffix)
+{
+  aFile->Append(NS_LITERAL_STRING("icons"));
+  aFile->Append(NS_LITERAL_STRING("default"));
+  aFile->Append(aIconName + aIconSuffix);
+
+  bool readable;
+  return NS_SUCCEEDED(aFile->IsReadable(&readable)) && readable;
+}
+
+/**
+ * Resolve the given icon name into a local file object.  This method is
+ * intended to be called by subclasses of nsBaseWidget.  aIconSuffix is a
+ * platform specific icon file suffix (e.g., ".ico" under Win32).
+ *
+ * If no file is found matching the given parameters, then null is returned.
+ */
+void
+nsBaseWidget::ResolveIconName(const nsAString &aIconName,
+                              const nsAString &aIconSuffix,
+                              nsIFile **aResult)
+{
+  *aResult = nullptr;
+
+  nsCOMPtr<nsIProperties> dirSvc = do_GetService(NS_DIRECTORY_SERVICE_CONTRACTID);
+  if (!dirSvc)
+    return;
+
+  // first check auxilary chrome directories
+
+  nsCOMPtr<nsISimpleEnumerator> dirs;
+  dirSvc->Get(NS_APP_CHROME_DIR_LIST, NS_GET_IID(nsISimpleEnumerator),
+              getter_AddRefs(dirs));
+  if (dirs) {
+    bool hasMore;
+    while (NS_SUCCEEDED(dirs->HasMoreElements(&hasMore)) && hasMore) {
+      nsCOMPtr<nsISupports> element;
+      dirs->GetNext(getter_AddRefs(element));
+      if (!element)
+        continue;
+      nsCOMPtr<nsIFile> file = do_QueryInterface(element);
+      if (!file)
+        continue;
+      if (ResolveIconNameHelper(file, aIconName, aIconSuffix)) {
+        NS_ADDREF(*aResult = file);
+        return;
+      }
+    }
+  }
+
+  // then check the main app chrome directory
+
+  nsCOMPtr<nsIFile> file;
+  dirSvc->Get(NS_APP_CHROME_DIR, NS_GET_IID(nsIFile),
+              getter_AddRefs(file));
+  if (file && ResolveIconNameHelper(file, aIconName, aIconSuffix))
+    NS_ADDREF(*aResult = file);
+}
+
+NS_IMETHODIMP
+nsBaseWidget::BeginResizeDrag(WidgetGUIEvent* aEvent,
+                              int32_t aHorizontal,
+                              int32_t aVertical)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP
+nsBaseWidget::BeginMoveDrag(WidgetMouseEvent* aEvent)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+void nsBaseWidget::SetSizeConstraints(const SizeConstraints& aConstraints)
+{
+  mSizeConstraints = aConstraints;
+  // We can't ensure that the size is honored at this point because we're
+  // probably in the middle of a reflow.
+}
+
+const widget::SizeConstraints nsBaseWidget::GetSizeConstraints()
+{
+  return mSizeConstraints;
+}
+
+// static
+nsIRollupListener*
+nsBaseWidget::GetActiveRollupListener()
+{
+  // If set, then this is likely an <html:select> dropdown.
+  if (gRollupListener)
+    return gRollupListener;
+
+  return nsXULPopupManager::GetInstance();
+}
+
+void
+nsBaseWidget::NotifyWindowDestroyed()
+{
+  if (!mWidgetListener)
+    return;
+
+  nsCOMPtr<nsIXULWindow> window = mWidgetListener->GetXULWindow();
+  nsCOMPtr<nsIBaseWindow> xulWindow(do_QueryInterface(window));
+  if (xulWindow) {
+    xulWindow->Destroy();
+  }
+}
+
+void
+nsBaseWidget::NotifySizeMoveDone()
+{
+  if (!mWidgetListener || mWidgetListener->GetXULWindow())
+    return;
+
+  nsIPresShell* presShell = mWidgetListener->GetPresShell();
+  if (presShell) {
+    presShell->WindowSizeMoveDone();
+  }
+}
+
+void
+nsBaseWidget::NotifyWindowMoved(int32_t aX, int32_t aY)
+{
+  if (mWidgetListener) {
+    mWidgetListener->WindowMoved(this, aX, aY);
+  }
+
+  if (mIMEHasFocus && GetIMEUpdatePreference().WantPositionChanged()) {
+    NotifyIME(IMENotification(IMEMessage::NOTIFY_IME_OF_POSITION_CHANGE));
+  }
+}
+
+void
+nsBaseWidget::NotifySysColorChanged()
+{
+  if (!mWidgetListener || mWidgetListener->GetXULWindow())
+    return;
+
+  nsIPresShell* presShell = mWidgetListener->GetPresShell();
+  if (presShell) {
+    presShell->SysColorChanged();
+  }
+}
+
+void
+nsBaseWidget::NotifyThemeChanged()
+{
+  if (!mWidgetListener || mWidgetListener->GetXULWindow())
+    return;
+
+  nsIPresShell* presShell = mWidgetListener->GetPresShell();
+  if (presShell) {
+    presShell->ThemeChanged();
+  }
+}
+
+void
+nsBaseWidget::NotifyUIStateChanged(UIStateChangeType aShowAccelerators,
+                                   UIStateChangeType aShowFocusRings)
+{
+  if (nsIDocument* doc = GetDocument()) {
+    nsPIDOMWindowOuter* win = doc->GetWindow();
+    if (win) {
+      win->SetKeyboardIndicators(aShowAccelerators, aShowFocusRings);
+    }
+  }
+}
+
+NS_IMETHODIMP
+nsBaseWidget::NotifyIME(const IMENotification& aIMENotification)
+{
+  switch (aIMENotification.mMessage) {
+    case REQUEST_TO_COMMIT_COMPOSITION:
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      // Currently, if native IME handler doesn't use TextEventDispatcher,
+      // the request may be notified to mTextEventDispatcher or native IME
+      // directly.  Therefore, if mTextEventDispatcher has a composition,
+      // the request should be handled by the mTextEventDispatcher.
+      if (mTextEventDispatcher && mTextEventDispatcher->IsComposing()) {
+        return mTextEventDispatcher->NotifyIME(aIMENotification);
+      }
+      // Otherwise, it should be handled by native IME.
+      return NotifyIMEInternal(aIMENotification);
+    default: {
+      if (aIMENotification.mMessage == NOTIFY_IME_OF_FOCUS) {
+        mIMEHasFocus = true;
+      }
+      EnsureTextEventDispatcher();
+      // If the platform specific widget uses TextEventDispatcher for handling
+      // native IME and keyboard events, IME event handler should be notified
+      // of the notification via TextEventDispatcher.  Otherwise, on the other
+      // platforms which have not used TextEventDispatcher yet, IME event
+      // handler should be notified by the old path (NotifyIMEInternal).
+      nsresult rv = mTextEventDispatcher->NotifyIME(aIMENotification);
+      nsresult rv2 = NotifyIMEInternal(aIMENotification);
+      if (aIMENotification.mMessage == NOTIFY_IME_OF_BLUR) {
+        mIMEHasFocus = false;
+      }
+      return rv2 == NS_ERROR_NOT_IMPLEMENTED ? rv : rv2;
+    }
+  }
+}
+
+void
+nsBaseWidget::EnsureTextEventDispatcher()
+{
+  if (mTextEventDispatcher) {
+    return;
+  }
+  mTextEventDispatcher = new TextEventDispatcher(this);
+}
+
+NS_IMETHODIMP_(nsIWidget::TextEventDispatcher*)
+nsBaseWidget::GetTextEventDispatcher()
+{
+  EnsureTextEventDispatcher();
+  return mTextEventDispatcher;
+}
+
+void*
+nsBaseWidget::GetPseudoIMEContext()
+{
+  TextEventDispatcher* dispatcher = GetTextEventDispatcher();
+  if (!dispatcher) {
+    return nullptr;
+  }
+  return dispatcher->GetPseudoIMEContext();
+}
+
+NS_IMETHODIMP_(TextEventDispatcherListener*)
+nsBaseWidget::GetNativeTextEventDispatcherListener()
+{
+  // TODO: If all platforms supported use of TextEventDispatcher for handling
+  //       native IME and keyboard events, this method should be removed since
+  //       in such case, this is overridden by all the subclasses.
+  return nullptr;
+}
+
+void
+nsBaseWidget::ZoomToRect(const uint32_t& aPresShellId,
+                         const FrameMetrics::ViewID& aViewId,
+                         const CSSRect& aRect,
+                         const uint32_t& aFlags)
+{
+  if (!mCompositorSession || !mAPZC) {
+    return;
+  }
+  uint64_t layerId = mCompositorSession->RootLayerTreeId();
+  mAPZC->ZoomToRect(ScrollableLayerGuid(layerId, aPresShellId, aViewId), aRect, aFlags);
+}
+
+#ifdef ACCESSIBILITY
+
+#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
+// defined in nsAppRunner.cpp
+extern const char* kAccessibilityLastRunDatePref;
+
+static inline uint32_t
+PRTimeToSeconds(PRTime t_usec)
+{
+  PRTime usec_per_sec = PR_USEC_PER_SEC;
+  return uint32_t(t_usec /= usec_per_sec);
+}
+#endif
+
+a11y::Accessible*
+nsBaseWidget::GetRootAccessible()
+{
+  NS_ENSURE_TRUE(mWidgetListener, nullptr);
+
+  nsIPresShell* presShell = mWidgetListener->GetPresShell();
+  NS_ENSURE_TRUE(presShell, nullptr);
+
+  // If container is null then the presshell is not active. This often happens
+  // when a preshell is being held onto for fastback.
+  nsPresContext* presContext = presShell->GetPresContext();
+  NS_ENSURE_TRUE(presContext->GetContainerWeak(), nullptr);
+
+  // Accessible creation might be not safe so use IsSafeToRunScript to
+  // make sure it's not created at unsafe times.
+  nsAccessibilityService* accService = GetOrCreateAccService();
+  if (accService) {
+#if defined(XP_WIN) || defined(XP_MACOSX) || defined(MOZ_WIDGET_GTK)
+    if (!mAccessibilityInUseFlag) {
+      mAccessibilityInUseFlag = true;
+      uint32_t now = PRTimeToSeconds(PR_Now());
+      Preferences::SetInt(kAccessibilityLastRunDatePref, now);
+    }
+#endif
+    return accService->GetRootDocumentAccessible(presShell, nsContentUtils::IsSafeToRunScript());
+  }
+
+  return nullptr;
+}
+
+#endif // ACCESSIBILITY
+
+void
+nsBaseWidget::StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics)
+{
+  if (!AsyncPanZoomEnabled()) {
+    return;
+  }
+
+  MOZ_ASSERT(XRE_IsParentProcess() && mCompositorSession);
+
+  int layersId = mCompositorSession->RootLayerTreeId();;
+  ScrollableLayerGuid guid(layersId, aDragMetrics.mPresShellId, aDragMetrics.mViewId);
+
+  APZThreadUtils::RunOnControllerThread(NewRunnableMethod
+    <ScrollableLayerGuid, AsyncDragMetrics>(mAPZC,
+                                            &IAPZCTreeManager::StartScrollbarDrag,
+                                            guid, aDragMetrics));
+}
+
+already_AddRefed<nsIScreen>
+nsBaseWidget::GetWidgetScreen()
+{
+  nsCOMPtr<nsIScreenManager> screenManager;
+  screenManager = do_GetService("@mozilla.org/gfx/screenmanager;1");
+  if (!screenManager) {
+    return nullptr;
+  }
+
+  LayoutDeviceIntRect bounds = GetScreenBounds();
+  DesktopIntRect deskBounds = RoundedToInt(bounds / GetDesktopToDeviceScale());
+  nsCOMPtr<nsIScreen> screen;
+  screenManager->ScreenForRect(deskBounds.x, deskBounds.y,
+                               deskBounds.width, deskBounds.height,
+                               getter_AddRefs(screen));
+  return screen.forget();
+}
+
+nsresult
+nsIWidget::SynthesizeNativeTouchTap(LayoutDeviceIntPoint aPoint, bool aLongTap,
+                                    nsIObserver* aObserver)
+{
+  AutoObserverNotifier notifier(aObserver, "touchtap");
+
+  if (sPointerIdCounter > TOUCH_INJECT_MAX_POINTS) {
+    sPointerIdCounter = 0;
+  }
+  int pointerId = sPointerIdCounter;
+  sPointerIdCounter++;
+  nsresult rv = SynthesizeNativeTouchPoint(pointerId, TOUCH_CONTACT,
+                                           aPoint, 1.0, 90, nullptr);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  if (!aLongTap) {
+    return SynthesizeNativeTouchPoint(pointerId, TOUCH_REMOVE,
+                                      aPoint, 0, 0, nullptr);
+  }
+
+  // initiate a long tap
+  int elapse = Preferences::GetInt("ui.click_hold_context_menus.delay",
+                                   TOUCH_INJECT_LONG_TAP_DEFAULT_MSEC);
+  if (!mLongTapTimer) {
+    mLongTapTimer = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
+    if (NS_FAILED(rv)) {
+      SynthesizeNativeTouchPoint(pointerId, TOUCH_CANCEL,
+                                 aPoint, 0, 0, nullptr);
+      return NS_ERROR_UNEXPECTED;
+    }
+    // Windows requires recuring events, so we set this to a smaller window
+    // than the pref value.
+    int timeout = elapse;
+    if (timeout > TOUCH_INJECT_PUMP_TIMER_MSEC) {
+      timeout = TOUCH_INJECT_PUMP_TIMER_MSEC;
+    }
+    mLongTapTimer->InitWithFuncCallback(OnLongTapTimerCallback, this,
+                                        timeout,
+                                        nsITimer::TYPE_REPEATING_SLACK);
+  }
+
+  // If we already have a long tap pending, cancel it. We only allow one long
+  // tap to be active at a time.
+  if (mLongTapTouchPoint) {
+    SynthesizeNativeTouchPoint(mLongTapTouchPoint->mPointerId, TOUCH_CANCEL,
+                               mLongTapTouchPoint->mPosition, 0, 0, nullptr);
+  }
+
+  mLongTapTouchPoint =
+    MakeUnique<LongTapInfo>(pointerId, aPoint,
+                            TimeDuration::FromMilliseconds(elapse),
+                            aObserver);
+  notifier.SkipNotification();  // we'll do it in the long-tap callback
+  return NS_OK;
+}
+
+// static
+void
+nsIWidget::OnLongTapTimerCallback(nsITimer* aTimer, void* aClosure)
+{
+  nsIWidget *self = static_cast<nsIWidget *>(aClosure);
+
+  if ((self->mLongTapTouchPoint->mStamp + self->mLongTapTouchPoint->mDuration) >
+      TimeStamp::Now()) {
+#ifdef XP_WIN
+    // Windows needs us to keep pumping feedback to the digitizer, so update
+    // the pointer id with the same position.
+    self->SynthesizeNativeTouchPoint(self->mLongTapTouchPoint->mPointerId,
+                                     TOUCH_CONTACT,
+                                     self->mLongTapTouchPoint->mPosition,
+                                     1.0, 90, nullptr);
+#endif
+    return;
+  }
+
+  AutoObserverNotifier notifier(self->mLongTapTouchPoint->mObserver, "touchtap");
+
+  // finished, remove the touch point
+  self->mLongTapTimer->Cancel();
+  self->mLongTapTimer = nullptr;
+  self->SynthesizeNativeTouchPoint(self->mLongTapTouchPoint->mPointerId,
+                                   TOUCH_REMOVE,
+                                   self->mLongTapTouchPoint->mPosition,
+                                   0, 0, nullptr);
+  self->mLongTapTouchPoint = nullptr;
+}
+
+nsresult
+nsIWidget::ClearNativeTouchSequence(nsIObserver* aObserver)
+{
+  AutoObserverNotifier notifier(aObserver, "cleartouch");
+
+  if (!mLongTapTimer) {
+    return NS_OK;
+  }
+  mLongTapTimer->Cancel();
+  mLongTapTimer = nullptr;
+  SynthesizeNativeTouchPoint(mLongTapTouchPoint->mPointerId, TOUCH_CANCEL,
+                             mLongTapTouchPoint->mPosition, 0, 0, nullptr);
+  mLongTapTouchPoint = nullptr;
+  return NS_OK;
+}
+
+MultiTouchInput
+nsBaseWidget::UpdateSynthesizedTouchState(MultiTouchInput* aState,
+                                          uint32_t aTime,
+                                          mozilla::TimeStamp aTimeStamp,
+                                          uint32_t aPointerId,
+                                          TouchPointerState aPointerState,
+                                          LayoutDeviceIntPoint aPoint,
+                                          double aPointerPressure,
+                                          uint32_t aPointerOrientation)
+{
+  ScreenIntPoint pointerScreenPoint = ViewAs<ScreenPixel>(aPoint,
+      PixelCastJustification::LayoutDeviceIsScreenForBounds);
+
+  // We can't dispatch *aState directly because (a) dispatching
+  // it might inadvertently modify it and (b) in the case of touchend or
+  // touchcancel events aState will hold the touches that are
+  // still down whereas the input dispatched needs to hold the removed
+  // touch(es). We use |inputToDispatch| for this purpose.
+  MultiTouchInput inputToDispatch;
+  inputToDispatch.mInputType = MULTITOUCH_INPUT;
+  inputToDispatch.mTime = aTime;
+  inputToDispatch.mTimeStamp = aTimeStamp;
+
+  int32_t index = aState->IndexOfTouch((int32_t)aPointerId);
+  if (aPointerState == TOUCH_CONTACT) {
+    if (index >= 0) {
+      // found an existing touch point, update it
+      SingleTouchData& point = aState->mTouches[index];
+      point.mScreenPoint = pointerScreenPoint;
+      point.mRotationAngle = (float)aPointerOrientation;
+      point.mForce = (float)aPointerPressure;
+      inputToDispatch.mType = MultiTouchInput::MULTITOUCH_MOVE;
+    } else {
+      // new touch point, add it
+      aState->mTouches.AppendElement(SingleTouchData(
+          (int32_t)aPointerId,
+          pointerScreenPoint,
+          ScreenSize(0, 0),
+          (float)aPointerOrientation,
+          (float)aPointerPressure));
+      inputToDispatch.mType = MultiTouchInput::MULTITOUCH_START;
+    }
+    inputToDispatch.mTouches = aState->mTouches;
+  } else {
+    MOZ_ASSERT(aPointerState == TOUCH_REMOVE || aPointerState == TOUCH_CANCEL);
+    // a touch point is being lifted, so remove it from the stored list
+    if (index >= 0) {
+      aState->mTouches.RemoveElementAt(index);
+    }
+    inputToDispatch.mType = (aPointerState == TOUCH_REMOVE
+        ? MultiTouchInput::MULTITOUCH_END
+        : MultiTouchInput::MULTITOUCH_CANCEL);
+    inputToDispatch.mTouches.AppendElement(SingleTouchData(
+        (int32_t)aPointerId,
+        pointerScreenPoint,
+        ScreenSize(0, 0),
+        (float)aPointerOrientation,
+        (float)aPointerPressure));
+  }
+
+  return inputToDispatch;
+}
+
+void
+nsBaseWidget::RegisterPluginWindowForRemoteUpdates()
+{
+#if !defined(XP_WIN) && !defined(MOZ_WIDGET_GTK)
+  NS_NOTREACHED("nsBaseWidget::RegisterPluginWindowForRemoteUpdates not implemented!");
+  return;
+#else
+  MOZ_ASSERT(NS_IsMainThread());
+  void* id = GetNativeData(NS_NATIVE_PLUGIN_ID);
+  if (!id) {
+    NS_WARNING("This is not a valid native widget!");
+    return;
+  }
+  MOZ_ASSERT(sPluginWidgetList);
+  sPluginWidgetList->Put(id, this);
+#endif
+}
+
+void
+nsBaseWidget::UnregisterPluginWindowForRemoteUpdates()
+{
+#if !defined(XP_WIN) && !defined(MOZ_WIDGET_GTK)
+  NS_NOTREACHED("nsBaseWidget::UnregisterPluginWindowForRemoteUpdates not implemented!");
+  return;
+#else
+  MOZ_ASSERT(NS_IsMainThread());
+  void* id = GetNativeData(NS_NATIVE_PLUGIN_ID);
+  if (!id) {
+    NS_WARNING("This is not a valid native widget!");
+    return;
+  }
+  MOZ_ASSERT(sPluginWidgetList);
+  sPluginWidgetList->Remove(id);
+#endif
+}
+
+// static
+nsIWidget*
+nsIWidget::LookupRegisteredPluginWindow(uintptr_t aWindowID)
+{
+#if !defined(XP_WIN) && !defined(MOZ_WIDGET_GTK)
+  NS_NOTREACHED("nsBaseWidget::LookupRegisteredPluginWindow not implemented!");
+  return nullptr;
+#else
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sPluginWidgetList);
+  return sPluginWidgetList->GetWeak((void*)aWindowID);
+#endif
+}
+
+// static
+void
+nsIWidget::UpdateRegisteredPluginWindowVisibility(uintptr_t aOwnerWidget,
+                                                  nsTArray<uintptr_t>& aPluginIds)
+{
+#if !defined(XP_WIN) && !defined(MOZ_WIDGET_GTK)
+  NS_NOTREACHED("nsBaseWidget::UpdateRegisteredPluginWindowVisibility not implemented!");
+  return;
+#else
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sPluginWidgetList);
+
+  // Our visible list is associated with a compositor which is associated with
+  // a specific top level window. We use the parent widget during iteration
+  // to skip the plugin widgets owned by other top level windows.
+  for (auto iter = sPluginWidgetList->Iter(); !iter.Done(); iter.Next()) {
+    const void* windowId = iter.Key();
+    nsIWidget* widget = iter.UserData();
+
+    MOZ_ASSERT(windowId);
+    MOZ_ASSERT(widget);
+
+    if (!widget->Destroyed()) {
+      if ((uintptr_t)widget->GetParent() == aOwnerWidget) {
+        widget->Show(aPluginIds.Contains((uintptr_t)windowId));
+      }
+    }
+  }
+#endif
+}
+
+#if defined(XP_WIN)
+// static
+void
+nsIWidget::CaptureRegisteredPlugins(uintptr_t aOwnerWidget)
+{
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sPluginWidgetList);
+
+  // Our visible list is associated with a compositor which is associated with
+  // a specific top level window. We use the parent widget during iteration
+  // to skip the plugin widgets owned by other top level windows.
+  for (auto iter = sPluginWidgetList->Iter(); !iter.Done(); iter.Next()) {
+    const void* windowId = iter.Key();
+    nsIWidget* widget = iter.UserData();
+
+    MOZ_ASSERT(windowId);
+    MOZ_ASSERT(widget);
+
+    if (!widget->Destroyed() && widget->IsVisible()) {
+      if ((uintptr_t)widget->GetParent() == aOwnerWidget) {
+        widget->UpdateScrollCapture();
+      }
+    }
+  }
+}
+
+uint64_t
+nsBaseWidget::CreateScrollCaptureContainer()
+{
+  mScrollCaptureContainer =
+    LayerManager::CreateImageContainer(ImageContainer::ASYNCHRONOUS);
+  if (!mScrollCaptureContainer) {
+    NS_WARNING("Failed to create ImageContainer for widget image capture.");
+    return ImageContainer::sInvalidAsyncContainerId;
+  }
+
+  return mScrollCaptureContainer->GetAsyncContainerID();
+}
+
+void
+nsBaseWidget::UpdateScrollCapture()
+{
+  // Don't capture if no container or no size.
+  if (!mScrollCaptureContainer || mBounds.width <= 0 || mBounds.height <= 0) {
+    return;
+  }
+
+  // If the derived class cannot take a snapshot, for example due to clipping,
+  // then it is responsible for creating a fallback. If null is returned, this
+  // means that we want to keep the existing snapshot.
+  RefPtr<gfx::SourceSurface> snapshot = CreateScrollSnapshot();
+  if (!snapshot) {
+    return;
+  }
+
+  ImageContainer::NonOwningImage holder(new SourceSurfaceImage(snapshot));
+
+  AutoTArray<ImageContainer::NonOwningImage, 1> imageList;
+  imageList.AppendElement(holder);
+
+  mScrollCaptureContainer->SetCurrentImages(imageList);
+}
+
+void
+nsBaseWidget::DefaultFillScrollCapture(DrawTarget* aSnapshotDrawTarget)
+{
+  gfx::IntSize dtSize = aSnapshotDrawTarget->GetSize();
+  aSnapshotDrawTarget->FillRect(
+    gfx::Rect(0, 0, dtSize.width, dtSize.height),
+    gfx::ColorPattern(gfx::Color::FromABGR(kScrollCaptureFillColor)),
+    gfx::DrawOptions(1.f, gfx::CompositionOp::OP_SOURCE));
+  aSnapshotDrawTarget->Flush();
+}
+#endif
+
+NS_IMETHODIMP_(nsIWidget::NativeIMEContext)
+nsIWidget::GetNativeIMEContext()
+{
+  return NativeIMEContext(this);
+}
+
+nsresult
+nsIWidget::OnWindowedPluginKeyEvent(const NativeEventData& aKeyEventData,
+                                    nsIKeyEventInPluginCallback* aCallback)
+{
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+namespace mozilla {
+namespace widget {
+
+const char*
+ToChar(IMEMessage aIMEMessage)
+{
+  switch (aIMEMessage) {
+    case NOTIFY_IME_OF_NOTHING:
+      return "NOTIFY_IME_OF_NOTHING";
+    case NOTIFY_IME_OF_FOCUS:
+      return "NOTIFY_IME_OF_FOCUS";
+    case NOTIFY_IME_OF_BLUR:
+      return "NOTIFY_IME_OF_BLUR";
+    case NOTIFY_IME_OF_SELECTION_CHANGE:
+      return "NOTIFY_IME_OF_SELECTION_CHANGE";
+    case NOTIFY_IME_OF_TEXT_CHANGE:
+      return "NOTIFY_IME_OF_TEXT_CHANGE";
+    case NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED:
+      return "NOTIFY_IME_OF_COMPOSITION_EVENT_HANDLED";
+    case NOTIFY_IME_OF_POSITION_CHANGE:
+      return "NOTIFY_IME_OF_POSITION_CHANGE";
+    case NOTIFY_IME_OF_MOUSE_BUTTON_EVENT:
+      return "NOTIFY_IME_OF_MOUSE_BUTTON_EVENT";
+    case REQUEST_TO_COMMIT_COMPOSITION:
+      return "REQUEST_TO_COMMIT_COMPOSITION";
+    case REQUEST_TO_CANCEL_COMPOSITION:
+      return "REQUEST_TO_CANCEL_COMPOSITION";
+    default:
+      return "Unexpected value";
+  }
+}
+
+void
+NativeIMEContext::Init(nsIWidget* aWidget)
+{
+  if (!aWidget) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(nullptr);
+    mOriginProcessID = static_cast<uint64_t>(-1);
+    return;
+  }
+  if (!XRE_IsContentProcess()) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(
+      aWidget->GetNativeData(NS_RAW_NATIVE_IME_CONTEXT));
+    mOriginProcessID = 0;
+    return;
+  }
+  // If this is created in a child process, aWidget is an instance of
+  // PuppetWidget which doesn't support NS_RAW_NATIVE_IME_CONTEXT.
+  // Instead of that PuppetWidget::GetNativeIMEContext() returns cached
+  // native IME context of the parent process.
+  *this = aWidget->GetNativeIMEContext();
+}
+
+void
+NativeIMEContext::InitWithRawNativeIMEContext(void* aRawNativeIMEContext)
+{
+  if (NS_WARN_IF(!aRawNativeIMEContext)) {
+    mRawNativeIMEContext = reinterpret_cast<uintptr_t>(nullptr);
+    mOriginProcessID = static_cast<uint64_t>(-1);
+    return;
+  }
+  mRawNativeIMEContext = reinterpret_cast<uintptr_t>(aRawNativeIMEContext);
+  mOriginProcessID =
+    XRE_IsContentProcess() ? ContentChild::GetSingleton()->GetID() : 0;
+}
+
+void
+IMENotification::TextChangeDataBase::MergeWith(
+                   const IMENotification::TextChangeDataBase& aOther)
+{
+  MOZ_ASSERT(aOther.IsValid(),
+             "Merging data must store valid data");
+  MOZ_ASSERT(aOther.mStartOffset <= aOther.mRemovedEndOffset,
+             "end of removed text must be same or larger than start");
+  MOZ_ASSERT(aOther.mStartOffset <= aOther.mAddedEndOffset,
+             "end of added text must be same or larger than start");
+
+  if (!IsValid()) {
+    *this = aOther;
+    return;
+  }
+
+  // |mStartOffset| and |mRemovedEndOffset| represent all replaced or removed
+  // text ranges.  I.e., mStartOffset should be the smallest offset of all
+  // modified text ranges in old text.  |mRemovedEndOffset| should be the
+  // largest end offset in old text of all modified text ranges.
+  // |mAddedEndOffset| represents the end offset of all inserted text ranges.
+  // I.e., only this is an offset in new text.
+  // In other words, between mStartOffset and |mRemovedEndOffset| of the
+  // premodified text was already removed.  And some text whose length is
+  // |mAddedEndOffset - mStartOffset| is inserted to |mStartOffset|.  I.e.,
+  // this allows IME to mark dirty the modified text range with |mStartOffset|
+  // and |mRemovedEndOffset| if IME stores all text of the focused editor and
+  // to compute new text length with |mAddedEndOffset| and |mRemovedEndOffset|.
+  // Additionally, IME can retrieve only the text between |mStartOffset| and
+  // |mAddedEndOffset| for updating stored text.
+
+  // For comparing new and old |mStartOffset|/|mRemovedEndOffset| values, they
+  // should be adjusted to be in same text. The |newData.mStartOffset| and
+  // |newData.mRemovedEndOffset| should be computed as in old text because
+  // |mStartOffset| and |mRemovedEndOffset| represent the modified text range
+  // in the old text but even if some text before the values of the newData
+  // has already been modified, the values don't include the changes.
+
+  // For comparing new and old |mAddedEndOffset| values, they should be
+  // adjusted to be in same text.  The |oldData.mAddedEndOffset| should be
+  // computed as in the new text because |mAddedEndOffset| indicates the end
+  // offset of inserted text in the new text but |oldData.mAddedEndOffset|
+  // doesn't include any changes of the text before |newData.mAddedEndOffset|.
+
+  const TextChangeDataBase& newData = aOther;
+  const TextChangeDataBase oldData = *this;
+
+  // mCausedOnlyByComposition should be true only when all changes are caused
+  // by composition.
+  mCausedOnlyByComposition =
+    newData.mCausedOnlyByComposition && oldData.mCausedOnlyByComposition;
+
+  // mIncludingChangesWithoutComposition should be true if at least one of
+  // merged changes occurred without composition.
+  mIncludingChangesWithoutComposition =
+    newData.mIncludingChangesWithoutComposition ||
+      oldData.mIncludingChangesWithoutComposition;
+
+  // mIncludingChangesDuringComposition should be true when at least one of
+  // the merged non-composition changes occurred during the latest composition.
+  if (!newData.mCausedOnlyByComposition &&
+      !newData.mIncludingChangesDuringComposition) {
+    MOZ_ASSERT(newData.mIncludingChangesWithoutComposition);
+    MOZ_ASSERT(mIncludingChangesWithoutComposition);
+    // If new change is neither caused by composition nor occurred during
+    // composition, set mIncludingChangesDuringComposition to false because
+    // IME doesn't want outdated text changes as text change during current
+    // composition.
+    mIncludingChangesDuringComposition = false;
+  } else {
+    // Otherwise, set mIncludingChangesDuringComposition to true if either
+    // oldData or newData includes changes during composition.
+    mIncludingChangesDuringComposition =
+      newData.mIncludingChangesDuringComposition ||
+        oldData.mIncludingChangesDuringComposition;
+  }
+
+  if (newData.mStartOffset >= oldData.mAddedEndOffset) {
+    // Case 1:
+    // If new start is after old end offset of added text, it means that text
+    // after the modified range is modified.  Like:
+    // added range of old change:             +----------+
+    // removed range of new change:                           +----------+
+    // So, the old start offset is always the smaller offset.
+    mStartOffset = oldData.mStartOffset;
+    // The new end offset of removed text is moved by the old change and we
+    // need to cancel the move of the old change for comparing the offsets in
+    // same text because it doesn't make sensce to compare offsets in different
+    // text.
+    uint32_t newRemovedEndOffsetInOldText =
+      newData.mRemovedEndOffset - oldData.Difference();
+    mRemovedEndOffset =
+      std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+    // The new end offset of added text is always the larger offset.
+    mAddedEndOffset = newData.mAddedEndOffset;
+    return;
+  }
+
+  if (newData.mStartOffset >= oldData.mStartOffset) {
+    // If new start is in the modified range, it means that new data changes
+    // a part or all of the range.
+    mStartOffset = oldData.mStartOffset;
+    if (newData.mRemovedEndOffset >= oldData.mAddedEndOffset) {
+      // Case 2:
+      // If new end of removed text is greater than old end of added text, it
+      // means that all or a part of modified range modified again and text
+      // after the modified range is also modified.  Like:
+      // added range of old change:             +----------+
+      // removed range of new change:                   +----------+
+      // So, the new removed end offset is moved by the old change and we need
+      // to cancel the move of the old change for comparing the offsets in the
+      // same text because it doesn't make sense to compare the offsets in
+      // different text.
+      uint32_t newRemovedEndOffsetInOldText =
+        newData.mRemovedEndOffset - oldData.Difference();
+      mRemovedEndOffset =
+        std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+      // The old end of added text is replaced by new change. So, it should be
+      // same as the new start.  On the other hand, the new added end offset is
+      // always same or larger.  Therefore, the merged end offset of added
+      // text should be the new end offset of added text.
+      mAddedEndOffset = newData.mAddedEndOffset;
+      return;
+    }
+
+    // Case 3:
+    // If new end of removed text is less than old end of added text, it means
+    // that only a part of the modified range is modified again.  Like:
+    // added range of old change:             +------------+
+    // removed range of new change:               +-----+
+    // So, the new end offset of removed text should be same as the old end
+    // offset of removed text.  Therefore, the merged end offset of removed
+    // text should be the old text change's |mRemovedEndOffset|.
+    mRemovedEndOffset = oldData.mRemovedEndOffset;
+    // The old end of added text is moved by new change.  So, we need to cancel
+    // the move of the new change for comparing the offsets in same text.
+    uint32_t oldAddedEndOffsetInNewText =
+      oldData.mAddedEndOffset + newData.Difference();
+    mAddedEndOffset =
+      std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+    return;
+  }
+
+  if (newData.mRemovedEndOffset >= oldData.mStartOffset) {
+    // If new end of removed text is greater than old start (and new start is
+    // less than old start), it means that a part of modified range is modified
+    // again and some new text before the modified range is also modified.
+    MOZ_ASSERT(newData.mStartOffset < oldData.mStartOffset,
+      "new start offset should be less than old one here");
+    mStartOffset = newData.mStartOffset;
+    if (newData.mRemovedEndOffset >= oldData.mAddedEndOffset) {
+      // Case 4:
+      // If new end of removed text is greater than old end of added text, it
+      // means that all modified text and text after the modified range is
+      // modified.  Like:
+      // added range of old change:             +----------+
+      // removed range of new change:        +------------------+
+      // So, the new end of removed text is moved by the old change.  Therefore,
+      // we need to cancel the move of the old change for comparing the offsets
+      // in same text because it doesn't make sense to compare the offsets in
+      // different text.
+      uint32_t newRemovedEndOffsetInOldText =
+        newData.mRemovedEndOffset - oldData.Difference();
+      mRemovedEndOffset =
+        std::max(newRemovedEndOffsetInOldText, oldData.mRemovedEndOffset);
+      // The old end of added text is replaced by new change.  So, the old end
+      // offset of added text is same as new text change's start offset.  Then,
+      // new change's end offset of added text is always same or larger than
+      // it.  Therefore, merged end offset of added text is always the new end
+      // offset of added text.
+      mAddedEndOffset = newData.mAddedEndOffset;
+      return;
+    }
+
+    // Case 5:
+    // If new end of removed text is less than old end of added text, it
+    // means that only a part of the modified range is modified again.  Like:
+    // added range of old change:             +----------+
+    // removed range of new change:      +----------+
+    // So, the new end of removed text should be same as old end of removed
+    // text for preventing end of removed text to be modified.  Therefore,
+    // merged end offset of removed text is always the old end offset of removed
+    // text.
+    mRemovedEndOffset = oldData.mRemovedEndOffset;
+    // The old end of added text is moved by this change.  So, we need to
+    // cancel the move of the new change for comparing the offsets in same text
+    // because it doesn't make sense to compare the offsets in different text.
+    uint32_t oldAddedEndOffsetInNewText =
+      oldData.mAddedEndOffset + newData.Difference();
+    mAddedEndOffset =
+      std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+    return;
+  }
+
+  // Case 6:
+  // Otherwise, i.e., both new end of added text and new start are less than
+  // old start, text before the modified range is modified.  Like:
+  // added range of old change:                  +----------+
+  // removed range of new change: +----------+
+  MOZ_ASSERT(newData.mStartOffset < oldData.mStartOffset,
+    "new start offset should be less than old one here");
+  mStartOffset = newData.mStartOffset;
+  MOZ_ASSERT(newData.mRemovedEndOffset < oldData.mRemovedEndOffset,
+     "new removed end offset should be less than old one here");
+  mRemovedEndOffset = oldData.mRemovedEndOffset;
+  // The end of added text should be adjusted with the new difference.
+  uint32_t oldAddedEndOffsetInNewText =
+    oldData.mAddedEndOffset + newData.Difference();
+  mAddedEndOffset =
+    std::max(newData.mAddedEndOffset, oldAddedEndOffsetInNewText);
+}
+
+#ifdef DEBUG
+
+// Let's test the code of merging multiple text change data in debug build
+// and crash if one of them fails because this feature is very complex but
+// cannot be tested with mochitest.
+void
+IMENotification::TextChangeDataBase::Test()
+{
+  static bool gTestTextChangeEvent = true;
+  if (!gTestTextChangeEvent) {
+    return;
+  }
+  gTestTextChangeEvent = false;
+
+  /****************************************************************************
+   * Case 1
+   ****************************************************************************/
+
+  // Appending text
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(20, 20, 35, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 1-1-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(mRemovedEndOffset == 10, // 20 - (20 - 10)
+    "Test 1-1-2: mRemovedEndOffset should be the first end of removed text");
+  MOZ_ASSERT(mAddedEndOffset == 35,
+    "Test 1-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text (longer line -> shorter line)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 30, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 1-2-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(mRemovedEndOffset == 40, // 30 + (10 - 20)
+    "Test 1-2-2: mRemovedEndOffset should be the the last end of removed text "
+    "with already removed length");
+  MOZ_ASSERT(mAddedEndOffset == 10,
+    "Test 1-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text (shorter line -> longer line)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(10, 15, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 1-3-1: mStartOffset should be the first offset");
+  MOZ_ASSERT(mRemovedEndOffset == 25, // 15 + (10 - 20)
+    "Test 1-3-2: mRemovedEndOffset should be the the last end of removed text "
+    "with already removed length");
+  MOZ_ASSERT(mAddedEndOffset == 10,
+    "Test 1-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Appending text at different point (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(55, 55, 60, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 1-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 45, // 55 - (10 - 20)
+    "Test 1-4-2: mRemovedEndOffset should be the the largest end of removed "
+    "text without already added length");
+  MOZ_ASSERT(mAddedEndOffset == 60,
+    "Test 1-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text at different point (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 20, 10, false, false));
+  MergeWith(TextChangeData(55, 68, 55, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 1-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 78, // 68 - (10 - 20)
+    "Test 1-5-2: mRemovedEndOffset should be the the largest end of removed "
+    "text with already removed length");
+  MOZ_ASSERT(mAddedEndOffset == 55,
+    "Test 1-5-3: mAddedEndOffset should be the largest end of added text");
+  Clear();
+
+  // Replacing text and append text (becomes longer)
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 40, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+    "Test 1-6-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 35, // 32 - (32 - 35)
+    "Test 1-6-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 40,
+    "Test 1-6-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text and append text (becomes shorter)
+  MergeWith(TextChangeData(30, 35, 32, false, false));
+  MergeWith(TextChangeData(32, 32, 33, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+    "Test 1-7-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 35, // 32 - (32 - 35)
+    "Test 1-7-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 33,
+    "Test 1-7-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text and replacing text after first range (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 34, 48, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+    "Test 1-8-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 39, // 34 - (30 - 35)
+    "Test 1-8-2: mRemovedEndOffset should be the the first end of removed text "
+    "without already removed text");
+  MOZ_ASSERT(mAddedEndOffset == 48,
+    "Test 1-8-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Removing text and replacing text after first range (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(32, 38, 36, false, false));
+  MOZ_ASSERT(mStartOffset == 30,
+    "Test 1-9-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 43, // 38 - (30 - 35)
+    "Test 1-9-2: mRemovedEndOffset should be the the first end of removed text "
+    "without already removed text");
+  MOZ_ASSERT(mAddedEndOffset == 36,
+    "Test 1-9-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 2
+   ****************************************************************************/
+
+  // Replacing text in around end of added text (becomes shorter) (not sure
+  // if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(53, 60, 54, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+    "Test 2-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 55, // 60 - (55 - 50)
+    "Test 2-1-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 54,
+    "Test 2-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of added text (becomes longer) (not sure
+  // if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(54, 62, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+    "Test 2-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 57, // 62 - (55 - 50)
+    "Test 2-2-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 68,
+    "Test 2-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(43, 50, 49, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+    "Test 2-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 53, // 50 - (45 - 48)
+    "Test 2-3-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already removed text length");
+  MOZ_ASSERT(mAddedEndOffset == 49,
+    "Test 2-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around end of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(36, 52, 53, false, false));
+  MergeWith(TextChangeData(43, 68, 61, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+    "Test 2-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 67, // 68 - (53 - 52)
+    "Test 2-4-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 61,
+    "Test 2-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 3
+   ****************************************************************************/
+
+  // Appending text in already added text (not sure if actually occurs)
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MergeWith(TextChangeData(15, 15, 30, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 3-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 10,
+    "Test 3-1-2: mRemovedEndOffset should be the the first end of removed text");
+  MOZ_ASSERT(mAddedEndOffset == 35, // 20 + (30 - 15)
+    "Test 3-1-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text in added text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(52, 53, 56, false, false));
+  MOZ_ASSERT(mStartOffset == 50,
+    "Test 3-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 50,
+    "Test 3-2-2: mRemovedEndOffset should be the the first end of removed text");
+  MOZ_ASSERT(mAddedEndOffset == 58, // 55 + (56 - 53)
+    "Test 3-2-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(36, 48, 45, false, false));
+  MergeWith(TextChangeData(37, 38, 50, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+    "Test 3-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+    "Test 3-3-2: mRemovedEndOffset should be the the first end of removed text");
+  MOZ_ASSERT(mAddedEndOffset == 57, // 45 + (50 - 38)
+    "Test 3-3-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 52, false, false));
+  MOZ_ASSERT(mStartOffset == 32,
+    "Test 3-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+    "Test 3-4-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 55, // 53 + (52 - 50)
+    "Test 3-4-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(36, 48, 50, false, false));
+  MergeWith(TextChangeData(37, 49, 47, false, false));
+  MOZ_ASSERT(mStartOffset == 36,
+    "Test 3-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+    "Test 3-5-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 48, // 50 + (47 - 49)
+    "Test 3-5-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+
+  // Replacing text in replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(32, 48, 53, false, false));
+  MergeWith(TextChangeData(43, 50, 47, false, false));
+  MOZ_ASSERT(mStartOffset == 32,
+    "Test 3-6-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 48,
+    "Test 3-6-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 50, // 53 + (47 - 50)
+    "Test 3-6-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+
+  /****************************************************************************
+   * Case 4
+   ****************************************************************************/
+
+  // Replacing text all of already append text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+    "Test 4-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 61, // 66 - (55 - 50)
+    "Test 4-1-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 68,
+    "Test 4-1-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text around a point in which text was removed (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 62, 50, false, false));
+  MergeWith(TextChangeData(44, 66, 68, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+    "Test 4-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 78, // 66 - (50 - 62)
+    "Test 4-2-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already removed text length");
+  MOZ_ASSERT(mAddedEndOffset == 68,
+    "Test 4-2-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text all replaced text (became shorter) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(50, 62, 60, false, false));
+  MergeWith(TextChangeData(49, 128, 130, false, false));
+  MOZ_ASSERT(mStartOffset == 49,
+    "Test 4-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 130, // 128 - (60 - 62)
+    "Test 4-3-2: mRemovedEndOffset should be the the last end of removed text "
+    "without already removed text length");
+  MOZ_ASSERT(mAddedEndOffset == 130,
+    "Test 4-3-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  // Replacing text all replaced text (became longer) (not sure if actually
+  // occurs)
+  MergeWith(TextChangeData(50, 61, 73, false, false));
+  MergeWith(TextChangeData(44, 100, 50, false, false));
+  MOZ_ASSERT(mStartOffset == 44,
+    "Test 4-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 88, // 100 - (73 - 61)
+    "Test 4-4-2: mRemovedEndOffset should be the the last end of removed text "
+    "with already added text length");
+  MOZ_ASSERT(mAddedEndOffset == 50,
+    "Test 4-4-3: mAddedEndOffset should be the last end of added text");
+  Clear();
+
+  /****************************************************************************
+   * Case 5
+   ****************************************************************************/
+
+  // Replacing text around start of added text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 50, 55, false, false));
+  MergeWith(TextChangeData(48, 52, 49, false, false));
+  MOZ_ASSERT(mStartOffset == 48,
+    "Test 5-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 50,
+    "Test 5-1-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 52, // 55 + (52 - 49)
+    "Test 5-1-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 48, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+    "Test 5-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 60,
+    "Test 5-2-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 56, // 58 + (48 - 50)
+    "Test 5-2-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 53, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+    "Test 5-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 60,
+    "Test 5-3-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 66, // 68 + (53 - 55)
+    "Test 5-3-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became shorter) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 58, false, false));
+  MergeWith(TextChangeData(43, 50, 128, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+    "Test 5-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 60,
+    "Test 5-4-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 136, // 58 + (128 - 50)
+    "Test 5-4-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Replacing text around start of replaced text (became longer) (not sure if
+  // actually occurs)
+  MergeWith(TextChangeData(50, 60, 68, false, false));
+  MergeWith(TextChangeData(43, 55, 65, false, false));
+  MOZ_ASSERT(mStartOffset == 43,
+    "Test 5-5-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 60,
+    "Test 5-5-2: mRemovedEndOffset should be the the first end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 78, // 68 + (65 - 55)
+    "Test 5-5-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  /****************************************************************************
+   * Case 6
+   ****************************************************************************/
+
+  // Appending text before already added text (not sure if actually occurs)
+  MergeWith(TextChangeData(30, 30, 45, false, false));
+  MergeWith(TextChangeData(10, 10, 20, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 6-1-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 30,
+    "Test 6-1-2: mRemovedEndOffset should be the the largest end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 55, // 45 + (20 - 10)
+    "Test 6-1-3: mAddedEndOffset should be the first end of added text with "
+    "added text length by the new change");
+  Clear();
+
+  // Removing text before already removed text (not sure if actually occurs)
+  MergeWith(TextChangeData(30, 35, 30, false, false));
+  MergeWith(TextChangeData(10, 25, 10, false, false));
+  MOZ_ASSERT(mStartOffset == 10,
+    "Test 6-2-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 35,
+    "Test 6-2-2: mRemovedEndOffset should be the the largest end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 15, // 30 - (25 - 10)
+    "Test 6-2-3: mAddedEndOffset should be the first end of added text with "
+    "removed text length by the new change");
+  Clear();
+
+  // Replacing text before already replaced text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 15, false, false));
+  MOZ_ASSERT(mStartOffset == 13,
+    "Test 6-3-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 65,
+    "Test 6-3-2: mRemovedEndOffset should be the the largest end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 61, // 70 + (15 - 24)
+    "Test 6-3-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+
+  // Replacing text before already replaced text (not sure if actually occurs)
+  MergeWith(TextChangeData(50, 65, 70, false, false));
+  MergeWith(TextChangeData(13, 24, 36, false, false));
+  MOZ_ASSERT(mStartOffset == 13,
+    "Test 6-4-1: mStartOffset should be the smallest offset");
+  MOZ_ASSERT(mRemovedEndOffset == 65,
+    "Test 6-4-2: mRemovedEndOffset should be the the largest end of removed "
+    "text");
+  MOZ_ASSERT(mAddedEndOffset == 82, // 70 + (36 - 24)
+    "Test 6-4-3: mAddedEndOffset should be the first end of added text without "
+    "removed text length by the new change");
+  Clear();
+}
+
+#endif // #ifdef DEBUG
+
+} // namespace widget
+} // namespace mozilla
+
+#ifdef DEBUG
+//////////////////////////////////////////////////////////////
+//
+// Convert a GUI event message code to a string.
+// Makes it a lot easier to debug events.
+//
+// See gtk/nsWidget.cpp and windows/nsWindow.cpp
+// for a DebugPrintEvent() function that uses
+// this.
+//
+//////////////////////////////////////////////////////////////
+/* static */ nsAutoString
+nsBaseWidget::debug_GuiEventToString(WidgetGUIEvent* aGuiEvent)
+{
+  NS_ASSERTION(nullptr != aGuiEvent,"cmon, null gui event.");
+
+  nsAutoString eventName(NS_LITERAL_STRING("UNKNOWN"));
+
+#define _ASSIGN_eventName(_value,_name)\
+case _value: eventName.AssignLiteral(_name) ; break
+
+  switch(aGuiEvent->mMessage)
+  {
+    _ASSIGN_eventName(eBlur,"eBlur");
+    _ASSIGN_eventName(eDrop,"eDrop");
+    _ASSIGN_eventName(eDragEnter,"eDragEnter");
+    _ASSIGN_eventName(eDragExit,"eDragExit");
+    _ASSIGN_eventName(eDragOver,"eDragOver");
+    _ASSIGN_eventName(eEditorInput,"eEditorInput");
+    _ASSIGN_eventName(eFocus,"eFocus");
+    _ASSIGN_eventName(eFocusIn,"eFocusIn");
+    _ASSIGN_eventName(eFocusOut,"eFocusOut");
+    _ASSIGN_eventName(eFormSelect,"eFormSelect");
+    _ASSIGN_eventName(eFormChange,"eFormChange");
+    _ASSIGN_eventName(eFormReset,"eFormReset");
+    _ASSIGN_eventName(eFormSubmit,"eFormSubmit");
+    _ASSIGN_eventName(eImageAbort,"eImageAbort");
+    _ASSIGN_eventName(eLoadError,"eLoadError");
+    _ASSIGN_eventName(eKeyDown,"eKeyDown");
+    _ASSIGN_eventName(eKeyPress,"eKeyPress");
+    _ASSIGN_eventName(eKeyUp,"eKeyUp");
+    _ASSIGN_eventName(eMouseEnterIntoWidget,"eMouseEnterIntoWidget");
+    _ASSIGN_eventName(eMouseExitFromWidget,"eMouseExitFromWidget");
+    _ASSIGN_eventName(eMouseDown,"eMouseDown");
+    _ASSIGN_eventName(eMouseUp,"eMouseUp");
+    _ASSIGN_eventName(eMouseClick,"eMouseClick");
+    _ASSIGN_eventName(eMouseDoubleClick,"eMouseDoubleClick");
+    _ASSIGN_eventName(eMouseMove,"eMouseMove");
+    _ASSIGN_eventName(eLoad,"eLoad");
+    _ASSIGN_eventName(ePopState,"ePopState");
+    _ASSIGN_eventName(eBeforeScriptExecute,"eBeforeScriptExecute");
+    _ASSIGN_eventName(eAfterScriptExecute,"eAfterScriptExecute");
+    _ASSIGN_eventName(eUnload,"eUnload");
+    _ASSIGN_eventName(eHashChange,"eHashChange");
+    _ASSIGN_eventName(eReadyStateChange,"eReadyStateChange");
+    _ASSIGN_eventName(eXULBroadcast, "eXULBroadcast");
+    _ASSIGN_eventName(eXULCommandUpdate, "eXULCommandUpdate");
+
+#undef _ASSIGN_eventName
+
+  default:
+    {
+      char buf[32];
+
+      SprintfLiteral(buf,"UNKNOWN: %d",aGuiEvent->mMessage);
+
+      CopyASCIItoUTF16(buf, eventName);
+    }
+    break;
+  }
+
+  return nsAutoString(eventName);
+}
+//////////////////////////////////////////////////////////////
+//
+// Code to deal with paint and event debug prefs.
+//
+//////////////////////////////////////////////////////////////
+struct PrefPair
+{
+  const char * name;
+  bool value;
+};
+
+static PrefPair debug_PrefValues[] =
+{
+  { "nglayout.debug.crossing_event_dumping", false },
+  { "nglayout.debug.event_dumping", false },
+  { "nglayout.debug.invalidate_dumping", false },
+  { "nglayout.debug.motion_event_dumping", false },
+  { "nglayout.debug.paint_dumping", false },
+  { "nglayout.debug.paint_flashing", false }
+};
+
+//////////////////////////////////////////////////////////////
+bool
+nsBaseWidget::debug_GetCachedBoolPref(const char * aPrefName)
+{
+  NS_ASSERTION(nullptr != aPrefName,"cmon, pref name is null.");
+
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++)
+  {
+    if (strcmp(debug_PrefValues[i].name, aPrefName) == 0)
+    {
+      return debug_PrefValues[i].value;
+    }
+  }
+
+  return false;
+}
+//////////////////////////////////////////////////////////////
+static void debug_SetCachedBoolPref(const char * aPrefName,bool aValue)
+{
+  NS_ASSERTION(nullptr != aPrefName,"cmon, pref name is null.");
+
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++)
+  {
+    if (strcmp(debug_PrefValues[i].name, aPrefName) == 0)
+    {
+      debug_PrefValues[i].value = aValue;
+
+      return;
+    }
+  }
+
+  NS_ASSERTION(false, "cmon, this code is not reached dude.");
+}
+
+//////////////////////////////////////////////////////////////
+class Debug_PrefObserver final : public nsIObserver {
+    ~Debug_PrefObserver() {}
+
+  public:
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIOBSERVER
+};
+
+NS_IMPL_ISUPPORTS(Debug_PrefObserver, nsIObserver)
+
+NS_IMETHODIMP
+Debug_PrefObserver::Observe(nsISupports* subject, const char* topic,
+                            const char16_t* data)
+{
+  NS_ConvertUTF16toUTF8 prefName(data);
+
+  bool value = Preferences::GetBool(prefName.get(), false);
+  debug_SetCachedBoolPref(prefName.get(), value);
+  return NS_OK;
+}
+
+//////////////////////////////////////////////////////////////
+/* static */ void
+debug_RegisterPrefCallbacks()
+{
+  static bool once = true;
+
+  if (!once) {
+    return;
+  }
+
+  once = false;
+
+  nsCOMPtr<nsIObserver> obs(new Debug_PrefObserver());
+  for (uint32_t i = 0; i < ArrayLength(debug_PrefValues); i++) {
+    // Initialize the pref values
+    debug_PrefValues[i].value =
+      Preferences::GetBool(debug_PrefValues[i].name, false);
+
+    if (obs) {
+      // Register callbacks for when these change
+      Preferences::AddStrongObserver(obs, debug_PrefValues[i].name);
+    }
+  }
+}
+//////////////////////////////////////////////////////////////
+static int32_t
+_GetPrintCount()
+{
+  static int32_t sCount = 0;
+
+  return ++sCount;
+}
+//////////////////////////////////////////////////////////////
+/* static */ bool
+nsBaseWidget::debug_WantPaintFlashing()
+{
+  return debug_GetCachedBoolPref("nglayout.debug.paint_flashing");
+}
+//////////////////////////////////////////////////////////////
+/* static */ void
+nsBaseWidget::debug_DumpEvent(FILE *                aFileOut,
+                              nsIWidget *           aWidget,
+                              WidgetGUIEvent*       aGuiEvent,
+                              const char*           aWidgetName,
+                              int32_t               aWindowID)
+{
+  if (aGuiEvent->mMessage == eMouseMove) {
+    if (!debug_GetCachedBoolPref("nglayout.debug.motion_event_dumping"))
+      return;
+  }
+
+  if (aGuiEvent->mMessage == eMouseEnterIntoWidget ||
+      aGuiEvent->mMessage == eMouseExitFromWidget) {
+    if (!debug_GetCachedBoolPref("nglayout.debug.crossing_event_dumping"))
+      return;
+  }
+
+  if (!debug_GetCachedBoolPref("nglayout.debug.event_dumping"))
+    return;
+
+  NS_LossyConvertUTF16toASCII tempString(debug_GuiEventToString(aGuiEvent).get());
+
+  fprintf(aFileOut,
+          "%4d %-26s widget=%-8p name=%-12s id=0x%-6x refpt=%d,%d\n",
+          _GetPrintCount(),
+          tempString.get(),
+          (void *) aWidget,
+          aWidgetName,
+          aWindowID,
+          aGuiEvent->mRefPoint.x,
+          aGuiEvent->mRefPoint.y);
+}
+//////////////////////////////////////////////////////////////
+/* static */ void
+nsBaseWidget::debug_DumpPaintEvent(FILE *                aFileOut,
+                                   nsIWidget *           aWidget,
+                                   const nsIntRegion &   aRegion,
+                                   const char *          aWidgetName,
+                                   int32_t               aWindowID)
+{
+  NS_ASSERTION(nullptr != aFileOut,"cmon, null output FILE");
+  NS_ASSERTION(nullptr != aWidget,"cmon, the widget is null");
+
+  if (!debug_GetCachedBoolPref("nglayout.debug.paint_dumping"))
+    return;
+
+  nsIntRect rect = aRegion.GetBounds();
+  fprintf(aFileOut,
+          "%4d PAINT      widget=%p name=%-12s id=0x%-6x bounds-rect=%3d,%-3d %3d,%-3d",
+          _GetPrintCount(),
+          (void *) aWidget,
+          aWidgetName,
+          aWindowID,
+          rect.x, rect.y, rect.width, rect.height
+    );
+
+  fprintf(aFileOut,"\n");
+}
+//////////////////////////////////////////////////////////////
+/* static */ void
+nsBaseWidget::debug_DumpInvalidate(FILE* aFileOut,
+                                   nsIWidget* aWidget,
+                                   const LayoutDeviceIntRect* aRect,
+                                   const char* aWidgetName,
+                                   int32_t aWindowID)
+{
+  if (!debug_GetCachedBoolPref("nglayout.debug.invalidate_dumping"))
+    return;
+
+  NS_ASSERTION(nullptr != aFileOut,"cmon, null output FILE");
+  NS_ASSERTION(nullptr != aWidget,"cmon, the widget is null");
+
+  fprintf(aFileOut,
+          "%4d Invalidate widget=%p name=%-12s id=0x%-6x",
+          _GetPrintCount(),
+          (void *) aWidget,
+          aWidgetName,
+          aWindowID);
+
+  if (aRect) {
+    fprintf(aFileOut,
+            " rect=%3d,%-3d %3d,%-3d",
+            aRect->x, aRect->y, aRect->width, aRect->height);
+  } else {
+    fprintf(aFileOut,
+            " rect=%-15s",
+            "none");
+  }
+
+  fprintf(aFileOut, "\n");
+}
+//////////////////////////////////////////////////////////////
+
+#endif // DEBUG