Run CSSOM smooth scroll animations on the compositor when possible

Source/platform/scroll/ScrollableArea.cpp

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 141 matching lines @@
         step = pixelStep(orientation);
         break;
     }
 
     if (direction == ScrollUp || direction == ScrollLeft)
         delta = -delta;
 
     return scrollAnimator()->scroll(orientation, granularity, step, delta);
 }
 
-void ScrollableArea::scrollToOffsetWithoutAnimation(const FloatPoint& offset)
+void ScrollableArea::scrollToOffsetWithoutAnimation(const FloatPoint& offset, bool cancelProgrammaticAnimations)
 {
-    cancelProgrammaticScrollAnimation();
+    if (cancelProgrammaticAnimations)
+        cancelProgrammaticScrollAnimation();
     scrollAnimator()->scrollToOffsetWithoutAnimation(offset);
 }
 
 void ScrollableArea::scrollToOffsetWithoutAnimation(ScrollbarOrientation orientation, float offset)
 {
     if (orientation == HorizontalScrollbar)
         scrollToOffsetWithoutAnimation(FloatPoint(offset, scrollAnimator()->currentPosition().y()));
     else
         scrollToOffsetWithoutAnimation(FloatPoint(scrollAnimator()->currentPosition().x(), offset));
 }
@@ skipping 248 matching lines @@
 {
     if (HostWindow* window = hostWindow()) {
         window->scheduleAnimation();
         return true;
     }
     return false;
 }
 
 void ScrollableArea::serviceScrollAnimations(double monotonicTime)
 {
-    bool hasRunningAnimation = false;
+    bool requiresAnimationService = false;
     if (ScrollAnimator* scrollAnimator = existingScrollAnimator()) {
         scrollAnimator->serviceScrollAnimations();
         if (scrollAnimator->hasRunningAnimation())
-            hasRunningAnimation = true;
+            requiresAnimationService = true;
     }
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator()) {
         programmaticScrollAnimator->tickAnimation(monotonicTime);
-        if (programmaticScrollAnimator->hasRunningAnimation())
-            hasRunningAnimation = true;
+        if (programmaticScrollAnimator->hasAnimationThatRequiresService())
+            requiresAnimationService = true;
     }
-    if (!hasRunningAnimation)
+    if (!requiresAnimationService)
         deregisterForAnimation();
 }
 
+void ScrollableArea::updateCompositorScrollAnimations()
+{
+    if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
+        programmaticScrollAnimator->updateCompositorAnimations();
+}
+
+void ScrollableArea::notifyCompositorAnimationFinished(int groupId)
+{
+    if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
+        programmaticScrollAnimator->notifyCompositorAnimationFinished(groupId);
+}
+
 void ScrollableArea::cancelProgrammaticScrollAnimation()
 {
     if (ProgrammaticScrollAnimator* programmaticScrollAnimator = existingProgrammaticScrollAnimator())
         programmaticScrollAnimator->cancelAnimation();
 }
 
 IntRect ScrollableArea::visibleContentRect(IncludeScrollbarsInRect scrollbarInclusion) const
 {
     int verticalScrollbarWidth = 0;
     int horizontalScrollbarHeight = 0;
@@ skipping 34 matching lines @@
 {
     return scrollSize(orientation);
 }
 
 float ScrollableArea::pixelStep(ScrollbarOrientation) const
 {
     return 1;
 }
 
 } // namespace blink