Run smooth scroll animations on the compositor when possible

third_party/WebKit/Source/platform/scroll/ScrollAnimator.h

 /*
  * Copyright (c) 2011, Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 16 matching lines @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef ScrollAnimator_h
 #define ScrollAnimator_h
 
 #include "platform/Timer.h"
 #include "platform/geometry/FloatPoint.h"
 #include "platform/scroll/ScrollAnimatorBase.h"
+#include "public/platform/WebCompositorAnimationDelegate.h"
+#include "public/platform/WebCompositorAnimationPlayerClient.h"
 #include "public/platform/WebScrollOffsetAnimationCurve.h"
 
 namespace blink {
 
 class ScrollAnimatorTest;
+class WebCompositorAnimationTimeline;
 
 class PLATFORM_EXPORT ScrollAnimator final : public ScrollAnimatorBase {
 public:
     explicit ScrollAnimator(ScrollableArea*, WTF::TimeFunction = WTF::monotonicallyIncreasingTime);
     ~ScrollAnimator() override;
 
     float computeDeltaToConsume(ScrollbarOrientation, float pixelDelta) const override;
 
     ScrollResultOneDimensional userScroll(ScrollbarOrientation, ScrollGranularity, float step, float delta) override;
     void scrollToOffsetWithoutAnimation(const FloatPoint&) override;
 
-    void cancelAnimations() override;
-    void serviceScrollAnimations() override;
-    bool hasRunningAnimation() const override;
+    // ScrollAnimatorCompositorCoordinator implementation.
+    void tickAnimation(double monotonicTime) override;
+    void cancelAnimation() override;
+    void resetAnimationState() override;
+    void updateCompositorAnimations() override;
+    void notifyCompositorAnimationFinished(int groupId) override;
+    void layerForCompositedScrollingDidChange(WebCompositorAnimationTimeline*) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
-    void animationTimerFired();
-
     OwnPtr<WebScrollOffsetAnimationCurve> m_animationCurve;
+    double m_lastTickTime;
     double m_startTime;
     WTF::TimeFunction m_timeFunction;
+
 private:
     FloatPoint desiredTargetPosition() const;
+
+    FloatPoint m_targetOffset;
 };
 
 } // namespace blink
 
 #endif // ScrollAnimator_h