Allow MainThreadEventQueue to call the RenderWidget directly.

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 e92696c4f8a96f65d80ed25e6348878bf9523638..ac9017b943e03f8cc6b0fc12fa86746e7c422737 100644
--- a/content/renderer/input/input_handler_manager.h
+++ b/content/renderer/input/input_handler_manager.h
@@ -24,7 +24,6 @@ struct InputHandlerScrollResult;
 }
 
 namespace blink {
-class WebInputEvent;
 class WebMouseWheelEvent;
 }
 
@@ -41,8 +40,9 @@ struct DidOverscrollParams;
 namespace content {
 
 class InputHandlerWrapper;
-class SynchronousInputHandlerProxyClient;
 class InputHandlerManagerClient;
+class MainThreadEventQueue;
+class SynchronousInputHandlerProxyClient;
 
 // InputHandlerManager class manages InputHandlerProxy instances for
 // the WebViews in this renderer.
@@ -60,12 +60,13 @@ class CONTENT_EXPORT InputHandlerManager {
   virtual ~InputHandlerManager();
 
   // Callable from the main thread only.
-  void AddInputHandler(int routing_id,
-                       const base::WeakPtr<cc::InputHandler>& input_handler,
-                       const base::WeakPtr<RenderWidget>& render_widget,
-                       bool enable_smooth_scrolling);
+  void AddInputHandler(
+      int routing_id,
+      const base::WeakPtr<cc::InputHandler>& input_handler,
+      const scoped_refptr<MainThreadEventQueue>& input_event_queue,
+      const base::WeakPtr<RenderWidget>& render_widget,
+      bool enable_smooth_scrolling);
 
-  void RegisterRoutingID(int routing_id);
   void UnregisterRoutingID(int routing_id);

[mustaq, 2017/04/12 19:27:49]

The UnregisterXYZ w/o a corresponding RegisterXYZ seems a bit too odd. CS seems
to suggest that there was no caller to RegisterXYZ before, but ~RenderFrameImpl
calls UnregisterXYZ. Is it real?

[dtapuska, 2017/04/13 16:56:24]

Yes; AddInputHandler and RegisterAssociatedRenderFrameRoutingID are the
"register" functions.

 
   void RegisterAssociatedRenderFrameRoutingID(int render_frame_routing_id,
@@ -79,13 +80,6 @@ class CONTENT_EXPORT InputHandlerManager {
       const blink::WebGestureEvent& gesture_event,
       const cc::InputHandlerScrollResult& scroll_result);
 
-  void NotifyInputEventHandledOnMainThread(int routing_id,
-                                           blink::WebInputEvent::Type,
-                                           blink::WebInputEventResult,
-                                           InputEventAckState);
-  void ProcessRafAlignedInputOnMainThread(int routing_id,
-                                          base::TimeTicks frame_time);
-
   // Callback only from the compositor's thread.
   void RemoveInputHandler(int routing_id);
 
@@ -113,9 +107,6 @@ class CONTENT_EXPORT InputHandlerManager {
   void DidAnimateForInput();
 
   // Called from the compositor's thread.
-  virtual void NeedsMainFrame(int routing_id);
-
-  // Called from the compositor's thread.
   void DispatchNonBlockingEventToMainThread(
       int routing_id,
       ui::WebScopedInputEvent event,
@@ -127,10 +118,10 @@ class CONTENT_EXPORT InputHandlerManager {
       int routing_id,
       const scoped_refptr<base::SingleThreadTaskRunner>& main_task_runner,
       const base::WeakPtr<cc::InputHandler>& input_handler,
+      const scoped_refptr<MainThreadEventQueue>& input_event_queue,
       const base::WeakPtr<RenderWidget>& render_widget,
       bool enable_smooth_scrolling);
 
-  void RegisterRoutingIDOnCompositorThread(int routing_id);
   void UnregisterRoutingIDOnCompositorThread(int routing_id);
 
   void ObserveWheelEventAndResultOnCompositorThread(