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 3403b82c5999d334dc61ac5ba7eb4d8b5ee61550..4587c3f7457826b906aa490c2e659af0ccae20b4 100644
--- a/content/renderer/input/input_handler_manager.h
+++ b/content/renderer/input/input_handler_manager.h
@@ -59,6 +59,8 @@ class CONTENT_EXPORT InputHandlerManager {
                        bool enable_smooth_scrolling,
                        bool enable_wheel_gestures);
 
+  void RegisterRoutingID(int routing_id);
+
   void ObserveWheelEventAndResultOnMainThread(
       int routing_id,
       const blink::WebMouseWheelEvent& wheel_event,
@@ -101,6 +103,8 @@ class CONTENT_EXPORT InputHandlerManager {
       bool enable_smooth_scrolling,
       bool enable_wheel_gestures);
 
+  void RegisterRoutingIDOnCompositorThread(int routing_id);
+
   void ObserveWheelEventAndResultOnCompositorThread(
       int routing_id,
       const blink::WebMouseWheelEvent& wheel_event,