Animated scroll shouldn't consume unhandled scrolls for OOPIFs.

cc/trees/layer_tree_host_client.h

Index: cc/trees/layer_tree_host_client.h
diff --git a/cc/trees/layer_tree_host_client.h b/cc/trees/layer_tree_host_client.h
index 03c2431f87476bcb135709d2745313b6e735d33d..75b96f119d376a28cbb107ab4c643b8649414b13 100644
--- a/cc/trees/layer_tree_host_client.h
+++ b/cc/trees/layer_tree_host_client.h
@@ -59,6 +59,8 @@ class LayerTreeHostClient {
   virtual void DidReceiveCompositorFrameAck() = 0;
   virtual void DidCompletePageScaleAnimation() = 0;
 
+  virtual bool IsForSubframe() = 0;

[Charlie Reis, 2017/04/18 21:59:03]

nit: No blank line before?  (Doesn't seem substantially different enough from
the ones above to need its own block.)  Same throughout the CL.

There's some ambiguity in the name-- is this only true for out-of-process
iframes, or could it ever be true on same-process subframes?  That seems worth
clarifying in a comment.

[wjmaclean, 2017/04/18 23:26:49]

Done.

+
  protected:
   virtual ~LayerTreeHostClient() {}
 };