Use swap-promise to improve first* paint times

third_party/WebKit/public/platform/WebLayerTreeView.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 15 matching lines @@
 #ifndef WebLayerTreeView_h
 #define WebLayerTreeView_h
 
 #include "WebBrowserControlsState.h"
 #include "WebColor.h"
 #include "WebCommon.h"
 #include "WebCompositorMutatorClient.h"
 #include "WebEventListenerProperties.h"
 #include "WebFloatPoint.h"
 #include "WebSize.h"
+#include "base/callback.h"
 #include "cc/surfaces/frame_sink_id.h"
 
 namespace cc {
 class AnimationHost;
 }
 
 namespace blink {
 
 class WebCompositeAndReadbackAsyncCallback;
 class WebLayer;
@@ skipping 128 matching lines @@
   virtual void SetShowFPSCounter(bool) {}
 
   // Toggles the paint rects in the HUD layer
   virtual void SetShowPaintRects(bool) {}
 
   // Toggles the debug borders on layers
   virtual void SetShowDebugBorders(bool) {}
 
   // Toggles scroll bottleneck rects on the HUD layer
   virtual void SetShowScrollBottleneckRects(bool) {}
+

[sunnyps, 2017/05/02 01:20:46]

nit: can you typedef or using the callback here? and document what the
parameters mean?

[panicker, 2017/05/02 21:21:36]

Done.

+  virtual void NotifySwapTime(base::Callback<void(bool, double)> callback) {}
 };
 
 }  // namespace blink
 
 #endif  // WebLayerTreeView_h