Send takeover msg from MT to CC using the animation path.

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

Index: third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h
diff --git a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h
index 2fa5de6a94a271b38de631c6fcb34592d3bd30e0..1a93c469374bfb9a9c7f0ff2a396529850b8de22 100644
--- a/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h
+++ b/third_party/WebKit/Source/platform/scroll/ScrollAnimatorCompositorCoordinator.h
@@ -34,7 +34,8 @@ public:
     void dispose();
     String runStateAsText() const;
 
-    void updateImplOnlyScrollOffsetAnimation(const FloatSize& adjustment);
+    void adjustImplOnlyScrollOffsetAnimation(const FloatSize& adjustment);
+    void takeoverImplOnlyScrollOffsetAnimation();
 
     virtual bool hasRunningAnimation() const { return false; }
 
@@ -59,6 +60,8 @@ protected:
 
     FloatSize implOnlyAnimationAdjustmentForTesting() { return m_implOnlyAnimationAdjustment; }
 
+    bool hasImplOnlyAnimationUpdate() const;
+
     bool addAnimation(PassOwnPtr<CompositorAnimation>);
     void removeAnimation();
     virtual void abortAnimation();
@@ -139,6 +142,10 @@ protected:
     // An adjustment to the scroll offset on the main thread that may affect
     // impl-only scroll offset animations.
     FloatSize m_implOnlyAnimationAdjustment;
+
+    // If set to true, sends a cc::ScrollOffsetAnimationUpdate to cc which will
+    // abort the impl-only scroll offset animation and continue it on mt.

[skobes, 2016/05/24 23:50:50]

spell out "main thread" for clarity

[ymalik, 2016/05/25 16:09:05]

Done.

+    bool m_implOnlyAnimationTakeover;
 };
 
 } // namespace blink