Plumb an overscroll callback form the compositor to the Android UI thread.

content/browser/renderer_host/render_widget_host_impl.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/render_widget_host_impl.h"
 
 #include <math.h>
 #include <utility>
 
 #include "base/auto_reset.h"
@@ skipping 1501 matching lines @@
     const cc::CompositorFrame& frame) {
 #if defined(OS_ANDROID)
   gfx::Vector2dF scroll_offset = ScaleVector2d(
       frame.metadata.root_scroll_offset, frame.metadata.page_scale_factor);
   gfx::SizeF content_size = ScaleSize(
       frame.metadata.root_layer_size, frame.metadata.page_scale_factor);
 
   if (view_) {
     view_->UpdateFrameInfo(
         gfx::ToRoundedVector2d(scroll_offset),
+        gfx::ToRoundedVector2d(frame.metadata.unused_scroll_delta),
         frame.metadata.page_scale_factor,
         frame.metadata.min_page_scale_factor,
         frame.metadata.max_page_scale_factor,
         gfx::ToCeiledSize(content_size),
         frame.metadata.location_bar_offset,
         frame.metadata.location_bar_content_translation);
   }
 #endif
 }
 
@@ skipping 830 matching lines @@
     return;
 
   OnRenderAutoResized(new_size);
 }
 
 void RenderWidgetHostImpl::DetachDelegate() {
   delegate_ = NULL;
 }
 
 }  // namespace content