Revert of Remove a frame of delay on main-thread FlingStart.

third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h

 /*
  * Copyright (C) 2012 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 28 matching lines @@
 // Implements a gesture animation (fling scroll, etc.) using a curve with a
 // generic interface to define the animation parameters as a function of time,
 // and applies the animation to a target, again via a generic interface. It is
 // assumed that animate() is called on a more-or-less regular basis by the
 // owner.
 class PLATFORM_EXPORT WebActiveGestureAnimation {
   USING_FAST_MALLOC(WebActiveGestureAnimation);
   WTF_MAKE_NONCOPYABLE(WebActiveGestureAnimation);
 
  public:
+  static std::unique_ptr<WebActiveGestureAnimation> CreateAtAnimationStart(
+      std::unique_ptr<WebGestureCurve>,
+      WebGestureCurveTarget*);
   static std::unique_ptr<WebActiveGestureAnimation> CreateWithTimeOffset(
       std::unique_ptr<WebGestureCurve>,
       WebGestureCurveTarget*,
       double start_time);
   ~WebActiveGestureAnimation();
 
   bool Animate(double time);
 
  private:
   // Assumes a valid WebGestureCurveTarget that outlives the animation.
   WebActiveGestureAnimation(std::unique_ptr<WebGestureCurve>,
                             WebGestureCurveTarget*,
-                            double start_time);
+                            double start_time,
+                            bool waiting_for_first_tick);
 
   double start_time_;
+  bool waiting_for_first_tick_;
   std::unique_ptr<WebGestureCurve> curve_;
   WebGestureCurveTarget* target_;
 };
 
 }  // namespace blink
 
 #endif