Change WebLayer::addAnimation to transfer ownership of WebAnimation.

public/platform/WebLayer.h

Index: public/platform/WebLayer.h
diff --git a/public/platform/WebLayer.h b/public/platform/WebLayer.h
index 67312e0a736324d3ac7fec063647e0efee99d8b1..ba39d6b2fddd8ce0a59164da1851429299f83e39 100644
--- a/public/platform/WebLayer.h
+++ b/public/platform/WebLayer.h
@@ -136,7 +136,12 @@ public:
     // deleting the delegate.
     virtual void setAnimationDelegate(WebAnimationDelegate*) = 0;
 
+    // TODO(dshwang): temporary macro to change addAnimation() in both Blink and Chromium.
+#define ANIMATION_OWNERSHIP_NOT_TRANSFER
+
     // Returns false if the animation cannot be added.
+    // It passes ownership of WebAnimation to Chromium.
+    // NOTE: Chromium owns the WebAnimation pointer.
     virtual bool addAnimation(WebAnimation*) = 0;
 
     // Removes all animations with the given id.