Fix viewport scroll bubbling of wheel events in CC.

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <set>
@@ skipping 2566 matching lines @@
 static gfx::Vector2dF ScrollLayerWithLocalDelta(
     LayerImpl* layer_impl,
     const gfx::Vector2dF& local_delta,
     float page_scale_factor) {
   gfx::ScrollOffset previous_offset = layer_impl->CurrentScrollOffset();
   gfx::Vector2dF delta = local_delta;
   delta.Scale(1.f / page_scale_factor);
   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,
                                               const gfx::Vector2dF& delta,
                                               const gfx::Point& viewport_point,
                                               bool is_wheel_scroll) {
   // Gesture events need to be transformed from viewport coordinates to
   // local layer coordinates so that the scrolling contents exactly follow
   // the user's finger. In contrast, wheel events represent a fixed amount
   // of scrolling so we can just apply them directly, but the page scale
@@ skipping 835 matching lines @@
   new_target.SetToMin(layer_impl->MaxScrollOffset());
 
   curve->UpdateTarget(
       animation->TrimTimeToCurrentIteration(CurrentBeginFrameArgs().frame_time)
           .InSecondsF(),
       new_target);
 
   return true;
 }
 }  // namespace cc