gecko-dev/widget/nsBaseWidget.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsBaseWidget_h__
#define nsBaseWidget_h__

#include "mozilla/EventForwards.h"
#include "mozilla/WidgetUtils.h"
#include "mozilla/layers/APZCCallbackHelper.h"
#include "nsRect.h"
#include "nsIWidget.h"
#include "nsWidgetsCID.h"
#include "nsIFile.h"
#include "nsString.h"
#include "nsCOMPtr.h"
#include "nsAutoPtr.h"
#include "nsIRollupListener.h"
#include "nsIObserver.h"
#include "nsIWidgetListener.h"
#include "nsPIDOMWindow.h"
#include "nsWeakReference.h"
#include <algorithm>
class nsIContent;
class nsAutoRollup;
class gfxContext;

namespace mozilla {
#ifdef ACCESSIBILITY
namespace a11y {
class Accessible;
}
#endif

namespace layers {
class BasicLayerManager;
class CompositorChild;
class CompositorParent;
class APZCTreeManager;
class GeckoContentController;
class APZEventState;
struct ScrollableLayerGuid;
} // namespace layers

class CompositorVsyncDispatcher;
} // namespace mozilla

namespace base {
class Thread;
} // namespace base

// Windows specific constant indicating the maximum number of touch points the
// inject api will allow. This also sets the maximum numerical value for touch
// ids we can use when injecting touch points on Windows.
#define TOUCH_INJECT_MAX_POINTS 256

class nsBaseWidget;

// Helper class used in shutting down gfx related code.
class WidgetShutdownObserver final : public nsIObserver
{
  ~WidgetShutdownObserver();

public:
  explicit WidgetShutdownObserver(nsBaseWidget* aWidget);

  NS_DECL_ISUPPORTS
  NS_DECL_NSIOBSERVER

  void Register();
  void Unregister();

  nsBaseWidget *mWidget;
  bool mRegistered;
};

/**
 * Common widget implementation used as base class for native
 * or crossplatform implementations of Widgets. 
 * All cross-platform behavior that all widgets need to implement 
 * should be placed in this class. 
 * (Note: widget implementations are not required to use this
 * class, but it gives them a head start.)
 */

class nsBaseWidget : public nsIWidget, public nsSupportsWeakReference
{
  friend class nsAutoRollup;
  friend class DispatchWheelEventOnMainThread;

protected:
  typedef base::Thread Thread;
  typedef mozilla::layers::BasicLayerManager BasicLayerManager;
  typedef mozilla::layers::BufferMode BufferMode;
  typedef mozilla::layers::CompositorChild CompositorChild;
  typedef mozilla::layers::CompositorParent CompositorParent;
  typedef mozilla::layers::APZCTreeManager APZCTreeManager;
  typedef mozilla::layers::GeckoContentController GeckoContentController;
  typedef mozilla::layers::ScrollableLayerGuid ScrollableLayerGuid;
  typedef mozilla::layers::APZEventState APZEventState;
  typedef mozilla::layers::SetAllowedTouchBehaviorCallback SetAllowedTouchBehaviorCallback;
  typedef mozilla::CSSIntRect CSSIntRect;
  typedef mozilla::CSSRect CSSRect;
  typedef mozilla::ScreenRotation ScreenRotation;

  virtual ~nsBaseWidget();

public:
  nsBaseWidget();

  NS_DECL_ISUPPORTS

  // nsIWidget interface
  NS_IMETHOD              CaptureMouse(bool aCapture) override;
  virtual nsIWidgetListener*  GetWidgetListener() override;
  virtual void            SetWidgetListener(nsIWidgetListener* alistener) override;
  NS_IMETHOD              Destroy() override;
  NS_IMETHOD              SetParent(nsIWidget* aNewParent) override;
  virtual nsIWidget*      GetParent(void) override;
  virtual nsIWidget*      GetTopLevelWidget() override;
  virtual nsIWidget*      GetSheetWindowParent(void) override;
  virtual float           GetDPI() override;
  virtual void            AddChild(nsIWidget* aChild) override;
  virtual void            RemoveChild(nsIWidget* aChild) override;

  void                    SetZIndex(int32_t aZIndex) override;
  NS_IMETHOD              PlaceBehind(nsTopLevelWidgetZPlacement aPlacement,
                                      nsIWidget *aWidget, bool aActivate) override;

  NS_IMETHOD              SetSizeMode(nsSizeMode aMode) override;
  virtual nsSizeMode      SizeMode() override
  {
    return mSizeMode;
  }

  virtual nsCursor        GetCursor() override;
  NS_IMETHOD              SetCursor(nsCursor aCursor) override;
  NS_IMETHOD              SetCursor(imgIContainer* aCursor,
                                    uint32_t aHotspotX, uint32_t aHotspotY) override;
  virtual void            ClearCachedCursor() override { mUpdateCursor = true; }
  virtual void            SetTransparencyMode(nsTransparencyMode aMode) override;
  virtual nsTransparencyMode GetTransparencyMode() override;
  virtual void            GetWindowClipRegion(nsTArray<LayoutDeviceIntRect>* aRects) override;
  NS_IMETHOD              SetWindowShadowStyle(int32_t aStyle) override;
  virtual void            SetShowsToolbarButton(bool aShow) override {}
  virtual void            SetShowsFullScreenButton(bool aShow) override {}
  virtual void            SetWindowAnimationType(WindowAnimationType aType) override {}
  NS_IMETHOD              HideWindowChrome(bool aShouldHide) override;
  virtual bool PrepareForFullscreenTransition(nsISupports** aData) override { return false; }
  virtual void PerformFullscreenTransition(FullscreenTransitionStage aStage,
                                           uint16_t aDuration,
                                           nsISupports* aData,
                                           nsIRunnable* aCallback) override;
  NS_IMETHOD              MakeFullScreen(bool aFullScreen, nsIScreen* aScreen = nullptr) override;

  virtual LayerManager*   GetLayerManager(PLayerTransactionChild* aShadowManager = nullptr,
                                          LayersBackend aBackendHint = mozilla::layers::LayersBackend::LAYERS_NONE,
                                          LayerManagerPersistence aPersistence = LAYER_MANAGER_CURRENT,
                                          bool* aAllowRetaining = nullptr) override;

  CompositorVsyncDispatcher* GetCompositorVsyncDispatcher() override;
  void            CreateCompositorVsyncDispatcher();
  virtual CompositorParent* NewCompositorParent(int aSurfaceWidth, int aSurfaceHeight);
  virtual void            CreateCompositor();
  virtual void            CreateCompositor(int aWidth, int aHeight);
  virtual void            PrepareWindowEffects() override {}
  virtual void            CleanupWindowEffects() override {}
  virtual bool            PreRender(LayerManagerComposite* aManager) override { return true; }
  virtual void            PostRender(LayerManagerComposite* aManager) override {}
  virtual void            DrawWindowUnderlay(LayerManagerComposite* aManager, LayoutDeviceIntRect aRect) override {}
  virtual void            DrawWindowOverlay(LayerManagerComposite* aManager, LayoutDeviceIntRect aRect) override {}
  virtual already_AddRefed<mozilla::gfx::DrawTarget> StartRemoteDrawing() override;
  virtual void            EndRemoteDrawing() override { };
  virtual void            CleanupRemoteDrawing() override { };
  virtual void            UpdateThemeGeometries(const nsTArray<ThemeGeometry>& aThemeGeometries) override {}
  NS_IMETHOD              SetModal(bool aModal) override;
  virtual uint32_t        GetMaxTouchPoints() const override;
  NS_IMETHOD              SetWindowClass(const nsAString& xulWinType) override;
  virtual nsresult        SetWindowClipRegion(const nsTArray<LayoutDeviceIntRect>& aRects, bool aIntersectWithExisting) override;
  // Return whether this widget interprets parameters to Move and Resize APIs
  // as "desktop pixels" rather than "device pixels", and therefore
  // applies its GetDefaultScale() value to them before using them as mBounds
  // etc (which are always stored in device pixels).
  // Note that APIs that -get- the widget's position/size/bounds, rather than
  // -setting- them (i.e. moving or resizing the widget) will always return
  // values in the widget's device pixels.
  bool                    BoundsUseDesktopPixels() const {
    return mWindowType <= eWindowType_popup;
  }
  // Default implementation, to be overridden by platforms where desktop coords
  // are virtualized and may not correspond to device pixels on the screen.
  mozilla::DesktopToLayoutDeviceScale GetDesktopToDeviceScale() override {
    return mozilla::DesktopToLayoutDeviceScale(1.0);
  }
  NS_IMETHOD              MoveClient(double aX, double aY) override;
  NS_IMETHOD              ResizeClient(double aWidth, double aHeight, bool aRepaint) override;
  NS_IMETHOD              ResizeClient(double aX, double aY, double aWidth, double aHeight, bool aRepaint) override;
  NS_IMETHOD              GetBounds(LayoutDeviceIntRect& aRect) override;
  NS_IMETHOD              GetClientBounds(LayoutDeviceIntRect& aRect) override;
  NS_IMETHOD              GetScreenBounds(LayoutDeviceIntRect& aRect) override;
  NS_IMETHOD              GetRestoredBounds(LayoutDeviceIntRect& aRect) override;
  NS_IMETHOD              GetNonClientMargins(LayoutDeviceIntMargin& aMargins) override;
  NS_IMETHOD              SetNonClientMargins(LayoutDeviceIntMargin& aMargins) override;
  virtual LayoutDeviceIntPoint GetClientOffset() override;
  NS_IMETHOD              EnableDragDrop(bool aEnable) override;
  NS_IMETHOD              GetAttention(int32_t aCycleCount) override;
  virtual bool            HasPendingInputEvent() override;
  NS_IMETHOD              SetIcon(const nsAString &anIconSpec) override;
  NS_IMETHOD              SetWindowTitlebarColor(nscolor aColor, bool aActive) override;
  virtual void            SetDrawsInTitlebar(bool aState) override {}
  virtual bool            ShowsResizeIndicator(LayoutDeviceIntRect* aResizerRect) override;
  virtual void            FreeNativeData(void * data, uint32_t aDataType) override {}
  NS_IMETHOD              BeginResizeDrag(mozilla::WidgetGUIEvent* aEvent,
                                          int32_t aHorizontal,
                                          int32_t aVertical) override;
  NS_IMETHOD              BeginMoveDrag(mozilla::WidgetMouseEvent* aEvent) override;
  virtual nsresult        ActivateNativeMenuItemAt(const nsAString& indexString) override { return NS_ERROR_NOT_IMPLEMENTED; }
  virtual nsresult        ForceUpdateNativeMenuAt(const nsAString& indexString) override { return NS_ERROR_NOT_IMPLEMENTED; }
  NS_IMETHOD              NotifyIME(const IMENotification& aIMENotification) override final;
  NS_IMETHOD              StartPluginIME(const mozilla::WidgetKeyboardEvent& aKeyboardEvent,
                                         int32_t aPanelX, int32_t aPanelY,
                                         nsString& aCommitted) override
                          { return NS_ERROR_NOT_IMPLEMENTED; }
  NS_IMETHOD              SetPluginFocused(bool& aFocused) override
                          { return NS_ERROR_NOT_IMPLEMENTED; }
  virtual void            SetCandidateWindowForPlugin(
                            const mozilla::widget::CandidateWindowPosition&
                              aPosition) override
                          { }
  virtual void            DefaultProcOfPluginEvent(
                            const mozilla::WidgetPluginEvent& aEvent) override
                          { }
  NS_IMETHOD              AttachNativeKeyEvent(mozilla::WidgetKeyboardEvent& aEvent) override { return NS_ERROR_NOT_IMPLEMENTED; }
  NS_IMETHOD_(bool)       ExecuteNativeKeyBinding(
                            NativeKeyBindingsType aType,
                            const mozilla::WidgetKeyboardEvent& aEvent,
                            DoCommandCallback aCallback,
                            void* aCallbackData) override { return false; }
  virtual bool            ComputeShouldAccelerate();
  virtual nsIMEUpdatePreference GetIMEUpdatePreference() override { return nsIMEUpdatePreference(); }
  NS_IMETHOD              OnDefaultButtonLoaded(const LayoutDeviceIntRect& aButtonRect) override { return NS_ERROR_NOT_IMPLEMENTED; }
  virtual already_AddRefed<nsIWidget>
  CreateChild(const LayoutDeviceIntRect& aRect,
              nsWidgetInitData* aInitData = nullptr,
              bool aForceUseIWidgetParent = false) override;
  NS_IMETHOD              AttachViewToTopLevel(bool aUseAttachedEvents) override;
  virtual nsIWidgetListener* GetAttachedWidgetListener() override;
  virtual void               SetAttachedWidgetListener(nsIWidgetListener* aListener) override;
  virtual nsIWidgetListener* GetPreviouslyAttachedWidgetListener() override;
  virtual void               SetPreviouslyAttachedWidgetListener(nsIWidgetListener* aListener) override;
  NS_IMETHOD_(TextEventDispatcher*) GetTextEventDispatcher() override final;
  NS_IMETHOD_(TextEventDispatcherListener*)
    GetNativeTextEventDispatcherListener() override;
  virtual void ZoomToRect(const uint32_t& aPresShellId,
                          const FrameMetrics::ViewID& aViewId,
                          const CSSRect& aRect,
                          const uint32_t& aFlags) override;
  // Dispatch an event that must be first be routed through APZ.
  nsEventStatus DispatchInputEvent(mozilla::WidgetInputEvent* aEvent) override;

  void SetConfirmedTargetAPZC(uint64_t aInputBlockId,
                              const nsTArray<ScrollableLayerGuid>& aTargets) const override;

  void UpdateZoomConstraints(const uint32_t& aPresShellId,
                             const FrameMetrics::ViewID& aViewId,
                             const mozilla::Maybe<ZoomConstraints>& aConstraints) override;

  bool AsyncPanZoomEnabled() const override;

  void NotifyWindowDestroyed();
  void NotifySizeMoveDone();
  void NotifyWindowMoved(int32_t aX, int32_t aY);

  // Register plugin windows for remote updates from the compositor
  virtual void RegisterPluginWindowForRemoteUpdates() override;
  virtual void UnregisterPluginWindowForRemoteUpdates() override;

  virtual void SetNativeData(uint32_t aDataType, uintptr_t aVal) override {};

  // Should be called by derived implementations to notify on system color and
  // theme changes.
  void NotifySysColorChanged();
  void NotifyThemeChanged();
  void NotifyUIStateChanged(UIStateChangeType aShowAccelerators,
                            UIStateChangeType aShowFocusRings);

#ifdef ACCESSIBILITY
  // Get the accessible for the window.
  mozilla::a11y::Accessible* GetRootAccessible();
#endif

  nsPopupLevel PopupLevel() { return mPopupLevel; }

  virtual LayoutDeviceIntSize
  ClientToWindowSize(const LayoutDeviceIntSize& aClientSize) override
  {
    return aClientSize;
  }

  // return the screen the widget is in.
  already_AddRefed<nsIScreen> GetWidgetScreen();

  // return true if this is a popup widget with a native titlebar
  bool IsPopupWithTitleBar() const
  {
    return (mWindowType == eWindowType_popup && 
            mBorderStyle != eBorderStyle_default &&
            mBorderStyle & eBorderStyle_title);
  }

  NS_IMETHOD              ReparentNativeWidget(nsIWidget* aNewParent) override = 0;

  virtual uint32_t GetGLFrameBufferFormat() override;

  virtual const SizeConstraints GetSizeConstraints() override;
  virtual void SetSizeConstraints(const SizeConstraints& aConstraints) override;

  virtual bool CaptureWidgetOnScreen(RefPtr<mozilla::gfx::DrawTarget> aDT) override {
    return false;
  }

  virtual void StartAsyncScrollbarDrag(const AsyncDragMetrics& aDragMetrics) override;

  /**
   * Use this when GetLayerManager() returns a BasicLayerManager
   * (nsBaseWidget::GetLayerManager() does). This sets up the widget's
   * layer manager to temporarily render into aTarget.
   *
   * |aNaturalWidgetBounds| is the un-rotated bounds of |aWidget|.
   * |aRotation| is the "virtual rotation" to apply when rendering to
   * the target.  When |aRotation| is ROTATION_0,
   * |aNaturalWidgetBounds| is not used.
   */
  class AutoLayerManagerSetup {
  public:
    AutoLayerManagerSetup(nsBaseWidget* aWidget, gfxContext* aTarget,
                          BufferMode aDoubleBuffering,
                          ScreenRotation aRotation = mozilla::ROTATION_0);
    ~AutoLayerManagerSetup();
  private:
    nsBaseWidget* mWidget;
    RefPtr<BasicLayerManager> mLayerManager;
  };
  friend class AutoLayerManagerSetup;

  virtual bool            ShouldUseOffMainThreadCompositing();

  static nsIRollupListener* GetActiveRollupListener();

  void Shutdown();

protected:

  void            ResolveIconName(const nsAString &aIconName,
                                  const nsAString &aIconSuffix,
                                  nsIFile **aResult);
  virtual void    OnDestroy();
  void            BaseCreate(nsIWidget *aParent,
                             nsWidgetInitData* aInitData);

  virtual void ConfigureAPZCTreeManager();
  virtual void ConfigureAPZControllerThread();
  virtual already_AddRefed<GeckoContentController> CreateRootContentController();

  // Dispatch an event that has already been routed through APZ.
  nsEventStatus ProcessUntransformedAPZEvent(mozilla::WidgetInputEvent* aEvent,
                                             const ScrollableLayerGuid& aGuid,
                                             uint64_t aInputBlockId,
                                             nsEventStatus aApzResponse);

  const LayoutDeviceIntRegion RegionFromArray(const nsTArray<LayoutDeviceIntRect>& aRects);
  void ArrayFromRegion(const LayoutDeviceIntRegion& aRegion,
                       nsTArray<LayoutDeviceIntRect>& aRects);

  virtual nsIContent* GetLastRollup() override
  {
    return mLastRollup;
  }

  virtual nsresult SynthesizeNativeKeyEvent(int32_t aNativeKeyboardLayout,
                                            int32_t aNativeKeyCode,
                                            uint32_t aModifierFlags,
                                            const nsAString& aCharacters,
                                            const nsAString& aUnmodifiedCharacters,
                                            nsIObserver* aObserver) override
  {
    mozilla::widget::AutoObserverNotifier notifier(aObserver, "keyevent");
    return NS_ERROR_UNEXPECTED;
  }

  virtual nsresult SynthesizeNativeMouseEvent(LayoutDeviceIntPoint aPoint,
                                              uint32_t aNativeMessage,
                                              uint32_t aModifierFlags,
                                              nsIObserver* aObserver) override
  {
    mozilla::widget::AutoObserverNotifier notifier(aObserver, "mouseevent");
    return NS_ERROR_UNEXPECTED;
  }

  virtual nsresult SynthesizeNativeMouseMove(LayoutDeviceIntPoint aPoint,
                                             nsIObserver* aObserver) override
  {
    mozilla::widget::AutoObserverNotifier notifier(aObserver, "mouseevent");
    return NS_ERROR_UNEXPECTED;
  }

  virtual nsresult SynthesizeNativeMouseScrollEvent(LayoutDeviceIntPoint aPoint,
                                                    uint32_t aNativeMessage,
                                                    double aDeltaX,
                                                    double aDeltaY,
                                                    double aDeltaZ,
                                                    uint32_t aModifierFlags,
                                                    uint32_t aAdditionalFlags,
                                                    nsIObserver* aObserver) override
  {
    mozilla::widget::AutoObserverNotifier notifier(aObserver, "mousescrollevent");
    return NS_ERROR_UNEXPECTED;
  }

  virtual nsresult SynthesizeNativeTouchPoint(uint32_t aPointerId,
                                              TouchPointerState aPointerState,
                                              ScreenIntPoint aPointerScreenPoint,
                                              double aPointerPressure,
                                              uint32_t aPointerOrientation,
                                              nsIObserver* aObserver) override
  {
    mozilla::widget::AutoObserverNotifier notifier(aObserver, "touchpoint");
    return NS_ERROR_UNEXPECTED;
  }

  virtual nsresult NotifyIMEInternal(const IMENotification& aIMENotification)
  { return NS_ERROR_NOT_IMPLEMENTED; }

  /**
   * GetPseudoIMEContext() returns pseudo IME context when TextEventDispatcher
   * has non-native input transaction.  Otherwise, returns nullptr.
   */
  void* GetPseudoIMEContext();

protected:
  // Utility to check if an array of clip rects is equal to our
  // internally stored clip rect array mClipRects.
  bool IsWindowClipRegionEqual(const nsTArray<LayoutDeviceIntRect>& aRects);

  // Stores the clip rectangles in aRects into mClipRects.
  void StoreWindowClipRegion(const nsTArray<LayoutDeviceIntRect>& aRects);

  virtual already_AddRefed<nsIWidget>
  AllocateChildPopupWidget()
  {
    static NS_DEFINE_IID(kCPopUpCID, NS_CHILD_CID);
    nsCOMPtr<nsIWidget> widget = do_CreateInstance(kCPopUpCID);
    return widget.forget();
  }

  LayerManager* CreateBasicLayerManager();

  nsPopupType PopupType() const { return mPopupType; }

  void NotifyRollupGeometryChange()
  {
    // XULPopupManager isn't interested in this notification, so only
    // send it if gRollupListener is set.
    if (gRollupListener) {
      gRollupListener->NotifyGeometryChange();
    }
  }

  /**
   * Apply the current size constraints to the given size.
   *
   * @param aWidth width to constrain
   * @param aHeight height to constrain
   */
  void ConstrainSize(int32_t* aWidth, int32_t* aHeight)
  {
    SizeConstraints c = GetSizeConstraints();
    *aWidth = std::max(c.mMinSize.width,
                       std::min(c.mMaxSize.width, *aWidth));
    *aHeight = std::max(c.mMinSize.height,
                        std::min(c.mMaxSize.height, *aHeight));
  }

  virtual CompositorChild* GetRemoteRenderer() override;

  /**
   * Notify the widget that this window is being used with OMTC.
   */
  virtual void WindowUsesOMTC() {}
  virtual void RegisterTouchWindow() {}

  nsIDocument* GetDocument() const;

 void EnsureTextEventDispatcher();

  // Notify the compositor that a device reset has occurred.
  void OnRenderingDeviceReset();

protected:
  /**
   * Starts the OMTC compositor destruction sequence.
   *
   * When this function returns, the compositor should not be 
   * able to access the opengl context anymore.
   * It is safe to call it several times if platform implementations
   * require the compositor to be destroyed before ~nsBaseWidget is
   * reached (This is the case with gtk2 for instance).
   */
  virtual void DestroyCompositor();
  void DestroyLayerManager();

  void FreeShutdownObserver();

  nsIWidgetListener* mWidgetListener;
  nsIWidgetListener* mAttachedWidgetListener;
  nsIWidgetListener* mPreviouslyAttachedWidgetListener;
  RefPtr<LayerManager> mLayerManager;
  RefPtr<CompositorChild> mCompositorChild;
  RefPtr<CompositorParent> mCompositorParent;
  RefPtr<mozilla::CompositorVsyncDispatcher> mCompositorVsyncDispatcher;
  RefPtr<APZCTreeManager> mAPZC;
  RefPtr<APZEventState> mAPZEventState;
  SetAllowedTouchBehaviorCallback mSetAllowedTouchBehaviorCallback;
  RefPtr<WidgetShutdownObserver> mShutdownObserver;
  RefPtr<TextEventDispatcher> mTextEventDispatcher;
  nsCursor          mCursor;
  nsBorderStyle     mBorderStyle;
  LayoutDeviceIntRect mBounds;
  LayoutDeviceIntRect* mOriginalBounds;
  // When this pointer is null, the widget is not clipped
  mozilla::UniquePtr<LayoutDeviceIntRect[]> mClipRects;
  uint32_t          mClipRectCount;
  nsSizeMode        mSizeMode;
  nsPopupLevel      mPopupLevel;
  nsPopupType       mPopupType;
  SizeConstraints   mSizeConstraints;

  bool              mUpdateCursor;
  bool              mUseAttachedEvents;
  bool              mIMEHasFocus;
#ifdef XP_WIN
  bool              mAccessibilityInUseFlag;
#endif
  static nsIRollupListener* gRollupListener;

  // the last rolled up popup. Only set this when an nsAutoRollup is in scope,
  // so it can be cleared automatically.
  static nsIContent* mLastRollup;

  struct InitialZoomConstraints {
    InitialZoomConstraints(const uint32_t& aPresShellID,
                           const FrameMetrics::ViewID& aViewID,
                           const ZoomConstraints& aConstraints)
      : mPresShellID(aPresShellID), mViewID(aViewID), mConstraints(aConstraints)
    {
    }

    uint32_t mPresShellID;
    FrameMetrics::ViewID mViewID;
    ZoomConstraints mConstraints;
  };

  mozilla::Maybe<InitialZoomConstraints> mInitialZoomConstraints;

#ifdef DEBUG
protected:
  static nsAutoString debug_GuiEventToString(mozilla::WidgetGUIEvent* aGuiEvent);
  static bool debug_WantPaintFlashing();

  static void debug_DumpInvalidate(FILE* aFileOut,
                                   nsIWidget* aWidget,
                                   const LayoutDeviceIntRect* aRect,
                                   const nsAutoCString& aWidgetName,
                                   int32_t aWindowID);

  static void debug_DumpEvent(FILE* aFileOut,
                              nsIWidget* aWidget,
                              mozilla::WidgetGUIEvent* aGuiEvent,
                              const nsAutoCString& aWidgetName,
                              int32_t aWindowID);

  static void debug_DumpPaintEvent(FILE *                aFileOut,
                                   nsIWidget *           aWidget,
                                   const nsIntRegion &   aPaintEvent,
                                   const nsAutoCString & aWidgetName,
                                   int32_t               aWindowID);

  static bool debug_GetCachedBoolPref(const char* aPrefName);
#endif
};

// A situation can occur when a mouse event occurs over a menu label while the
// menu popup is already open. The expected behaviour is to close the popup.
// This happens by calling nsIRollupListener::Rollup before the mouse event is
// processed. However, in cases where the mouse event is not consumed, this
// event will then get targeted at the menu label causing the menu to open
// again. To prevent this, we store in mLastRollup a reference to the popup
// that was closed during the Rollup call, and prevent this popup from
// reopening while processing the mouse event.
// mLastRollup should only be set while an nsAutoRollup is in scope;
// when it goes out of scope mLastRollup is cleared automatically.
// As mLastRollup is static, it can be retrieved by calling
// nsIWidget::GetLastRollup on any widget.
class nsAutoRollup
{
  bool wasClear;

  public:

  nsAutoRollup();
  ~nsAutoRollup();
};

#endif // nsBaseWidget_h__