Respect the order of input messages from browser to renderer

content/renderer/input/input_handler_manager.h

Index: content/renderer/input/input_handler_manager.h
diff --git a/content/renderer/input/input_handler_manager.h b/content/renderer/input/input_handler_manager.h
index ee693def31ac6dc9db27cef3c6bac80ae9c2924a..7ebc8b305fdbf2fbfb01321cfb1c9108f774e6a0 100644
--- a/content/renderer/input/input_handler_manager.h
+++ b/content/renderer/input/input_handler_manager.h
@@ -58,6 +58,9 @@ class CONTENT_EXPORT InputHandlerManager {
                        const base::WeakPtr<RenderViewImpl>& render_view_impl,
                        bool enable_smooth_scrolling);
 
+  void RegisterRoutingID(int routing_id);
+  void UnregisterRoutingID(int routing_id);
+
   void ObserveWheelEventAndResultOnMainThread(
       int routing_id,
       const blink::WebMouseWheelEvent& wheel_event,
@@ -99,6 +102,9 @@ class CONTENT_EXPORT InputHandlerManager {
       const base::WeakPtr<RenderViewImpl>& render_view_impl,
       bool enable_smooth_scrolling);
 
+  void RegisterRoutingIDOnCompositorThread(int routing_id);
+  void UnregisterRoutingIDOnCompositorThread(int routing_id);
+
   void ObserveWheelEventAndResultOnCompositorThread(
       int routing_id,
       const blink::WebMouseWheelEvent& wheel_event,