Blink Support for Overlay Scrollbar Animation

Source/platform/scroll/ScrollableArea.h

 /*
  * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 22 matching lines @@
 #include "wtf/Vector.h"
 
 namespace blink {
 
 class FloatPoint;
 class GraphicsLayer;
 class HostWindow;
 class PlatformWheelEvent;
 class ProgrammaticScrollAnimator;
 class ScrollAnimator;
+class ScrollbarStateTransitionAnimator;
 
 enum ScrollBehavior {
     ScrollBehaviorAuto,
     ScrollBehaviorInstant,
     ScrollBehaviorSmooth,
 };
 
 enum IncludeScrollbarsInRect {
     ExcludeScrollbars,
     IncludeScrollbars,
@@ skipping 47 matching lines @@
     void contentAreaDidShow() const;
     void contentAreaDidHide() const;
 
     void finishCurrentScrollAnimations() const;
 
     virtual void didAddScrollbar(Scrollbar*, ScrollbarOrientation);
     virtual void willRemoveScrollbar(Scrollbar*, ScrollbarOrientation);
 
     virtual void contentsResized();
 
-    bool hasOverlayScrollbars() const;
+    virtual bool hasOverlayScrollbars() const;
     void setScrollbarOverlayStyle(ScrollbarOverlayStyle);
     ScrollbarOverlayStyle scrollbarOverlayStyle() const { return static_cast<ScrollbarOverlayStyle>(m_scrollbarOverlayStyle); }
 
     // This getter will create a ScrollAnimator if it doesn't already exist.
     ScrollAnimator* scrollAnimator() const;
 
     // This getter will return null if the ScrollAnimator hasn't been created yet.
     ScrollAnimator* existingScrollAnimator() const { return m_animators ? m_animators->scrollAnimator.get() : 0; }
 
     ProgrammaticScrollAnimator* programmaticScrollAnimator() const;
     ProgrammaticScrollAnimator* existingProgrammaticScrollAnimator() const
     {
         return m_animators ? m_animators->programmaticScrollAnimator.get() : 0;
     }
 
+    // This getter will create a ScrollbarStateTransitionAnimator if needed and doesn't already exist.
+    ScrollbarStateTransitionAnimator* scrollbarStateTransitionAnimator() const;
+    // This getter will return null if the ScrollbarStateTransitionAnimator hasn't been created yet.
+    ScrollbarStateTransitionAnimator* existingScrollbarStateTransitionAnimator() const
+    {
+        return m_animators ? m_animators->scrollbarStateTransitionAnimator.get() : 0;
+    }
+
+    bool isDuringStateTransitionAnimation() const;
+    void stateTransitionInProgress();
+
     const IntPoint& scrollOrigin() const { return m_scrollOrigin; }
     bool scrollOriginChanged() const { return m_scrollOriginChanged; }
 
     // FIXME(bokan): Meaningless name, rename to isActiveFocus
     virtual bool isActive() const = 0;
     virtual int scrollSize(ScrollbarOrientation) const = 0;
     virtual void invalidateScrollbar(Scrollbar*, const IntRect&);
     virtual bool isScrollCornerVisible() const = 0;
     virtual IntRect scrollCornerRect() const = 0;
     virtual void invalidateScrollCorner(const IntRect&);
@@ skipping 49 matching lines @@
 
     // NOTE: Only called from Internals for testing.
     void setScrollOffsetFromInternals(const IntPoint&);
 
     IntPoint clampScrollPosition(const IntPoint&) const;
 
     // Let subclasses provide a way of asking for and servicing scroll
     // animations.
     bool scheduleAnimation();
     void serviceScrollAnimations(double monotonicTime);
+    void serviceScrollbarAnimations();
 
     virtual bool usesCompositedScrolling() const { return false; }
 
     // Returns true if the GraphicsLayer tree needs to be rebuilt.
     virtual bool updateAfterCompositingChange() { return false; }
 
     virtual bool userInputScrollable(ScrollbarOrientation) const = 0;
     virtual bool shouldPlaceVerticalScrollbarOnLeft() const = 0;
 
     // Convenience functions
@@ skipping 58 matching lines @@
     virtual int documentStep(ScrollbarOrientation) const;
     virtual float pixelStep(ScrollbarOrientation) const;
 
     // Stores the paint invalidations for the scrollbars during layout.
     IntRect m_horizontalBarDamage;
     IntRect m_verticalBarDamage;
 
     struct ScrollableAreaAnimators {
         OwnPtr<ScrollAnimator> scrollAnimator;
         OwnPtr<ProgrammaticScrollAnimator> programmaticScrollAnimator;
+        OwnPtr<ScrollbarStateTransitionAnimator> scrollbarStateTransitionAnimator;
     };
 
     mutable OwnPtr<ScrollableAreaAnimators> m_animators;
     unsigned m_constrainsScrollingToContentEdge : 1;
 
     unsigned m_inLiveResize : 1;
 
     unsigned m_verticalScrollElasticity : 2; // ScrollElasticity
     unsigned m_horizontalScrollElasticity : 2; // ScrollElasticity
 
@@ skipping 11 matching lines @@
     // vertical-lr / ltr            NO                      NO
     // vertical-lr / rtl            NO                      YES
     // vertical-rl / ltr            YES                     NO
     // vertical-rl / rtl            YES                     YES
     IntPoint m_scrollOrigin;
 };
 
 } // namespace blink
 
 #endif // ScrollableArea_h