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

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

Index: third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h
diff --git a/third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h b/third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h
index e1adc588e050e6e4c1643bcde6232222940d2c79..45b29d4fab8393f6e05af5d97f3e555b62134922 100644
--- a/third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h
+++ b/third_party/WebKit/Source/platform/exported/WebActiveGestureAnimation.h
@@ -46,6 +46,9 @@
   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*,
@@ -58,9 +61,11 @@
   // 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_;
 };