Delegate root layer scroll offset to android_webview.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index 3660f75d57c2a3636a61edd176e106dcd4db4f43..be41d6cceffe2f6d29044d1f684890107eb71575 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -53,7 +53,10 @@ struct WebPoint;
 struct WebRenderingStatsImpl;
 }
 
-namespace cc { class OutputSurface; }
+namespace cc {
+class InputHandlerClient;
+class OutputSurface;
+}
 
 namespace ui {
 class Range;
@@ -73,6 +76,7 @@ namespace content {
 struct GpuRenderingStats;
 class RenderWidgetCompositor;
 class RenderWidgetTest;
+class SynchronousCompositorImpl;
 
 // RenderWidget provides a communication bridge between a WebWidget and
 // a RenderWidgetHost, the latter of which lives in a different process.
@@ -175,6 +179,7 @@ class CONTENT_EXPORT RenderWidget
   RenderWidgetCompositor* compositor() const;
 
   virtual scoped_ptr<cc::OutputSurface> CreateOutputSurface();
+  scoped_ptr<cc::InputHandlerClient> CreateInputHandlerClient();
 
   // Callback for use with BeginSmoothScroll.
   typedef base::Callback<void()> SmoothScrollCompletionCallback;
@@ -494,6 +499,9 @@ class CONTENT_EXPORT RenderWidget
   WebGraphicsContext3DCommandBufferImpl* CreateGraphicsContext3D(
       const WebKit::WebGraphicsContext3D::Attributes& attributes);
 
+  // Lazily creates the synchronous compositor on first call.
+  SynchronousCompositorImpl* GetSynchronousCompositor();
+
   bool OnSnapshotHelper(const gfx::Rect& src_subrect, SkBitmap* bitmap);
 
   // Routing ID that allows us to communicate to the parent browser process
@@ -508,6 +516,11 @@ class CONTENT_EXPORT RenderWidget
   // This is lazily constructed and must not outlive webwidget_.
   scoped_ptr<RenderWidgetCompositor> compositor_;
 
+#if defined(OS_ANDROID)
+  // This is lazily constructed.
+  scoped_ptr<SynchronousCompositorImpl> synchronous_compositor_;
+#endif
+
   // Set to the ID of the view that initiated creating this view, if any. When
   // the view was initiated by the browser (the common case), this will be
   // MSG_ROUTING_NONE. This is used in determining ownership when opening