Share animations from compositor to main thread.

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

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h b/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
index 18469bd8b62264e91bb39445364dab045cdf17d7..98f8b4a699a4d380b8cac76595309f8f40329f3b 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimator.h
@@ -67,6 +67,11 @@ public:
     DECLARE_VIRTUAL_TRACE();
 
 protected:
+    void notifyAnimationTakeover(
+        double monotonicTime,
+        double animationStartTime,
+        scoped_ptr<cc::AnimationCurve>) override;
+
     OwnPtr<CompositorScrollOffsetAnimationCurve> m_animationCurve;
     double m_startTime;
     WTF::TimeFunction m_timeFunction;
@@ -82,6 +87,9 @@ private:
     void addMainThreadScrollingReason();
     void removeMainThreadScrollingReason();
 
+    // Returns true if will animate to the given target position.

[ajuma, 2016/02/26 23:56:54]

Please expand this to include the sorts of things that would cause us to animate
or not animate.

[ymalik, 2016/02/29 16:31:09]

Done.

+    bool willAnimateToOffset(const FloatPoint& targetPos);
+
     FloatPoint m_targetOffset;
     ScrollGranularity m_lastGranularity;
 };