[VSync Queue] Flush input in CommitComplete()

cc/input/input_handler.h

 // Copyright 2011 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 CC_INPUT_INPUT_HANDLER_H_
 #define CC_INPUT_INPUT_HANDLER_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 92 matching lines @@
     WHEEL,
     NON_BUBBLING_GESTURE
   };
 
   enum class TouchStartEventListenerType {
     NO_HANDLER,
     HANDLER,
     HANDLER_ON_SCROLLING_LAYER
   };
 
+  enum class InputHandlerState {

[dtapuska, 2017/04/27 16:24:44]

This name seems a bit too generic.

[chongz, 2017/04/27 19:12:14]

Changed to READY_FOR_INPUT and BUSY_INSIDE_IMPL_FRAME, or do you have other
suggestions?

[chongz, 2017/04/28 19:21:21]

Changed enum name to |ImplThreadPhase|.

+    IDLE,
+    INSIDE_IMPL_FRAME,
+  };
+
   // Binds a client to this handler to receive notifications. Only one client
   // can be bound to an InputHandler. The client must live at least until the
   // handler calls WillShutdown() on the client.
   virtual void BindToClient(InputHandlerClient* client,
                             bool wheel_scroll_latching_enabled) = 0;
 
+  // |InputHandlerClient| should avoid delivering input events during
+  // |INSIDE_IMPL_FRAME| to reduce checkerboard issue.
+  virtual InputHandlerState GetInputHandlerState() const = 0;
+
   // Selects a layer to be scrolled using the |scroll_state| start position.
   // Returns SCROLL_STARTED if the layer at the coordinates can be scrolled,
   // SCROLL_ON_MAIN_THREAD if the scroll event should instead be delegated to
   // the main thread, or SCROLL_IGNORED if there is nothing to be scrolled at
   // the given coordinates.
   virtual ScrollStatus ScrollBegin(ScrollState* scroll_state,
                                    ScrollInputType type) = 0;
 
   // Similar to ScrollBegin, except the hit test is skipped and scroll always
   // targets at the root layer.
@@ skipping 94 matching lines @@
   InputHandler() {}
   virtual ~InputHandler() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InputHandler);
 };
 
 }  // namespace cc
 
 #endif  // CC_INPUT_INPUT_HANDLER_H_