Share animations from compositor to main thread.

third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h

Index: third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h
diff --git a/third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h b/third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h
index 58339f8069ee70f936f3357941daf346d0c65c87..78e8959e35a527f6946cea2bf097c417589fe6eb 100644
--- a/third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h
+++ b/third_party/WebKit/public/platform/WebCompositorAnimationDelegate.h
@@ -6,6 +6,7 @@
 #define WebCompositorAnimationDelegate_h
 
 #include "WebCommon.h"
+#include "cc/animation/animation_curve.h"
 
 namespace blink {
 
@@ -16,6 +17,14 @@ public:
     virtual void notifyAnimationStarted(double monotonicTime, int group) = 0;
     virtual void notifyAnimationFinished(double monotonicTime, int group) = 0;
     virtual void notifyAnimationAborted(double monotonicTime, int group) = 0;
+    // In the current state of things, notifyAnimationTakeover only applies to
+    // scroll offset animations since main thread scrolling reasons can be added
+    // while the compositor is animating. Keeping this non-pure virtual since
+    // it doesn't apply to CSS animations.
+    virtual void notifyAnimationTakeover(
+        double monotonicTime,
+        double animationStartTime,
+        scoped_ptr<cc::AnimationCurve> curve) { }
 };
 
 } // namespace blink