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

third_party/WebKit/Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 681 matching lines @@
       fling_modifier_ = event.GetModifiers();
       fling_source_device_ = event.source_device;
       DCHECK_NE(fling_source_device_, kWebGestureDeviceUninitialized);
       std::unique_ptr<WebGestureCurve> fling_curve =
           Platform::Current()->CreateFlingAnimationCurve(
               event.source_device,
               WebFloatPoint(event.data.fling_start.velocity_x,
                             event.data.fling_start.velocity_y),
               WebSize());
       DCHECK(fling_curve);
-      gesture_animation_ = WebActiveGestureAnimation::CreateWithTimeOffset(
-          std::move(fling_curve), this, event.TimeStampSeconds());
+      gesture_animation_ = WebActiveGestureAnimation::CreateAtAnimationStart(
+          std::move(fling_curve), this);
       MainFrameImpl()->FrameWidget()->ScheduleAnimation();
       event_result = WebInputEventResult::kHandledSystem;
 
       WebGestureEvent scaled_event =
           TransformWebGestureEvent(MainFrameImpl()->GetFrameView(), event);
       // Plugins may need to see GestureFlingStart to balance
       // GestureScrollBegin (since the former replaces GestureScrollEnd when
       // transitioning to a fling).
       // TODO(dtapuska): Why isn't the response used?
       MainFrameImpl()->GetFrame()->GetEventHandler().HandleGestureScrollEvent(
@@ skipping 3437 matching lines @@
   if (focused_frame->LocalFrameRoot() != MainFrameImpl()->GetFrame())
     return nullptr;
   return focused_frame;
 }
 
 LocalFrame* WebViewImpl::FocusedLocalFrameAvailableForIme() const {
   return ime_accept_events_ ? FocusedLocalFrameInWidget() : nullptr;
 }
 
 }  // namespace blink