Let LayerTreeHostImpl::ScrollAnimated scroll the outer viewport.

cc/input/input_handler.h

Index: cc/input/input_handler.h
diff --git a/cc/input/input_handler.h b/cc/input/input_handler.h
index 4696fb5ceca81d7c6cc4678935cc8317292d83bf..424b5ad0d0c54c6d22c3e9c4d6ce72a23467822f 100644
--- a/cc/input/input_handler.h
+++ b/cc/input/input_handler.h
@@ -84,7 +84,7 @@ class CC_EXPORT InputHandler {
     // This must be the last entry.
     ScrollStatusCount
   };
-  enum ScrollInputType { GESTURE, WHEEL, NON_BUBBLING_GESTURE };
+  enum ScrollInputType { GESTURE, WHEEL, ANIMATED_WHEEL, NON_BUBBLING_GESTURE };
 
   // Binds a client to this handler to receive notifications. Only one client
   // can be bound to an InputHandler. The client must live at least until the
@@ -153,7 +153,7 @@ class CC_EXPORT InputHandler {
 
   // If there is a scroll active, this reports whether the scroll is on the
   // root layer, or on some other sublayer.

[tdresser, 2015/10/20 12:29:40]

Should we update this comment?

[skobes, 2015/10/20 18:28:15]

Done.

-  virtual bool IsCurrentlyScrollingRoot() const = 0;
+  virtual bool IsCurrentlyScrollingInnerViewport() const = 0;
 
   // Whether the layer under |viewport_point| is the currently scrolling layer.
   virtual bool IsCurrentlyScrollingLayerAt(const gfx::Point& viewport_point,