Fix viewport scroll bubbling of wheel events in CC.

cc/trees/layer_tree_host_impl.cc

Index: cc/trees/layer_tree_host_impl.cc
diff --git a/cc/trees/layer_tree_host_impl.cc b/cc/trees/layer_tree_host_impl.cc
index f75077da63a2f4824a17d6d37a44f078f784be5c..90f8cd83806a91c881fb5d2c190323766ba61f61 100644
--- a/cc/trees/layer_tree_host_impl.cc
+++ b/cc/trees/layer_tree_host_impl.cc
@@ -2584,7 +2584,10 @@ static gfx::Vector2dF ScrollLayerWithLocalDelta(
   layer_impl->ScrollBy(delta);
   gfx::ScrollOffset scrolled =
       layer_impl->CurrentScrollOffset() - previous_offset;
-  return gfx::Vector2dF(scrolled.x(), scrolled.y());
+  gfx::Vector2dF consumed_scroll(scrolled.x(), scrolled.y());
+  consumed_scroll.Scale(page_scale_factor);
+
+  return consumed_scroll;
 }
 
 gfx::Vector2dF LayerTreeHostImpl::ScrollLayer(LayerImpl* layer_impl,