Implement Main Thread RAF Aligned Input

content/renderer/input/input_event_filter.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_INPUT_INPUT_EVENT_FILTER_H_
 #define CONTENT_RENDERER_INPUT_INPUT_EVENT_FILTER_H_
 
 #include <queue>
 #include <set>
 #include <unordered_map>
@@ skipping 52 matching lines @@
   void SetBoundHandler(const Handler& handler) override;
   void RegisterRoutingID(int routing_id) override;
   void UnregisterRoutingID(int routing_id) override;
   void DidOverscroll(int routing_id,
                      const DidOverscrollParams& params) override;
   void DidStartFlinging(int routing_id) override;
   void DidStopFlinging(int routing_id) override;
   void NotifyInputEventHandled(int routing_id,
                                blink::WebInputEvent::Type type,
                                InputEventAckState ack_result) override;
+  void ProcessVSyncAlignedInput(int routing_id) override;

[tdresser, 2016/07/20 21:43:08]

I think we want to align with rAF more than we want to align with vsync.
Normally they're the same, but they won't always be (if I understand correctly).

 
   // IPC::MessageFilter methods:
   void OnFilterAdded(IPC::Sender* sender) override;
   void OnFilterRemoved() override;
   void OnChannelClosing() override;
   bool OnMessageReceived(const IPC::Message& message) override;
 
   // MainThreadEventQueueClient methods:
   void HandleEventOnMainThread(int routing_id,
                                const blink::WebInputEvent* event,
@@ skipping 39 matching lines @@
   // 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<DidOverscrollParams>* current_overscroll_params_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_INPUT_INPUT_EVENT_FILTER_H_