Refactor compositor event handling path to be callback-based

content/renderer/input/input_event_filter.h

Index: content/renderer/input/input_event_filter.h
diff --git a/content/renderer/input/input_event_filter.h b/content/renderer/input/input_event_filter.h
index 6ebe7f42515ef04d75f99605450120e56620fc16..2226fd799d1dc030d17e6c77e26df6523379dd1e 100644
--- a/content/renderer/input/input_event_filter.h
+++ b/content/renderer/input/input_event_filter.h
@@ -65,7 +65,8 @@ class CONTENT_EXPORT InputEventFilter : public InputHandlerManagerClient,
   void RegisterRoutingID(int routing_id) override;
   void UnregisterRoutingID(int routing_id) override;
   void DidOverscroll(int routing_id,
-                     const ui::DidOverscrollParams& params) override;
+                     const ui::DidOverscrollParams& params,
+                     bool bundle_ack_with_triggering_event) override;
   void DidStartFlinging(int routing_id) override;
   void DidStopFlinging(int routing_id) override;
   void NotifyInputEventHandled(int routing_id,
@@ -95,6 +96,13 @@ class CONTENT_EXPORT InputEventFilter : public InputHandlerManagerClient,
   ~InputEventFilter() override;
 
   void ForwardToHandler(const IPC::Message& message);
+  void DidForwardToHandler(
+      int routing_id,
+      InputEventDispatchType dispatch_type,
+      InputEventAckState ack_state,
+      ui::ScopedWebInputEvent event,
+      const ui::LatencyInfo& latency_info,
+      std::unique_ptr<ui::DidOverscrollParams> overscroll_params);
   void SendMessage(std::unique_ptr<IPC::Message> message);
   void SendMessageOnIOThread(std::unique_ptr<IPC::Message> message);
   void SetIsFlingingInMainThreadEventQueue(int routing_id, bool is_flinging);
@@ -120,11 +128,6 @@ class CONTENT_EXPORT InputEventFilter : public InputHandlerManagerClient,
       std::unordered_map<int, scoped_refptr<MainThreadEventQueue>>;
   RouteQueueMap route_queues_;
 
-  // Used to intercept overscroll notifications while an event is being
-  // dispatched.  If the event causes overscroll, the overscroll metadata can be
-  // bundled in the event ack, saving an IPC.  Note that we must continue
-  // supporting overscroll IPC notifications due to fling animation updates.
-  std::unique_ptr<ui::DidOverscrollParams>* current_overscroll_params_;

[chongz, 2016/08/23 04:35:24]

|DidOverscrollParams| handling moved to |InputHandlerProxy|.

   blink::scheduler::RendererScheduler* renderer_scheduler_;
 };