Delegate root layer scroll offset to android_webview.

content/renderer/gpu/input_handler_manager.h

Index: content/renderer/gpu/input_handler_manager.h
diff --git a/content/renderer/gpu/input_handler_manager.h b/content/renderer/gpu/input_handler_manager.h
index c33b5b772fdc75b8872145bcc109917a17a3c1cd..5915702431c9283d6623dffdeda17e4d469055c0 100644
--- a/content/renderer/gpu/input_handler_manager.h
+++ b/content/renderer/gpu/input_handler_manager.h
@@ -17,6 +17,7 @@ class MessageLoopProxy;
 
 namespace cc {
 class InputHandler;
+class LayerScrollOffsetDelegate;
 }
 
 namespace WebKit {
@@ -51,6 +52,13 @@ class InputHandlerManager {
       const base::WeakPtr<cc::InputHandler>& input_handler,
       const base::WeakPtr<RenderViewImpl>& render_view_impl);
 
+  // Callable from the main thread only.
+  // |layer_scroll_delegate| will be accessed from the Compositor Impl thread
+  // and must outlive the InputHandler that it's associated with.
+  void SetRootLayerScrollDelegate(
+      int routing_id,
+      cc::LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate);
+
   // Callback only from the compositor's thread.
   void RemoveInputHandler(int routing_id);
 
@@ -69,6 +77,10 @@ class InputHandlerManager {
       const base::WeakPtr<cc::InputHandler>& input_handler,
       const base::WeakPtr<RenderViewImpl>& render_view_impl);
 
+  void SetRootLayerScrollDelegateOnCompositorThread(
+      int routing_id,
+      cc::LayerScrollOffsetDelegate* root_layer_scroll_offset_delegate);
+
   typedef std::map<int,  // routing_id
                    scoped_refptr<InputHandlerWrapper> > InputHandlerMap;
   InputHandlerMap input_handlers_;