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

content/browser/renderer_host/render_widget_host_view_guest.h

Index: content/browser/renderer_host/render_widget_host_view_guest.h
diff --git a/content/browser/renderer_host/render_widget_host_view_guest.h b/content/browser/renderer_host/render_widget_host_view_guest.h
index a58c0e77e96a25866523fe0f2e8ab09d3b4b33e0..788290b2bc4f3000ff5b70af5f98cae1942caded 100644
--- a/content/browser/renderer_host/render_widget_host_view_guest.h
+++ b/content/browser/renderer_host/render_widget_host_view_guest.h
@@ -156,6 +156,7 @@ class CONTENT_EXPORT RenderWidgetHostViewGuest
   virtual void SetCachedPageScaleFactorLimits(float minimum_scale,
                                               float maximum_scale) OVERRIDE;
   virtual void UpdateFrameInfo(const gfx::Vector2d& scroll_offset,
+                               const gfx::Vector2d& unused_scroll_delta,
                                float page_scale_factor,
                                float min_page_scale_factor,
                                float max_page_scale_factor,