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

third_party/WebKit/Source/web/WebViewImpl.cpp

Index: third_party/WebKit/Source/web/WebViewImpl.cpp
diff --git a/third_party/WebKit/Source/web/WebViewImpl.cpp b/third_party/WebKit/Source/web/WebViewImpl.cpp
index f6a890a5ba39f4bbe686b9d61f9d09263f0dfebb..12e2e3b5158be4287dad2dbcdbe675b124fe4413 100644
--- a/third_party/WebKit/Source/web/WebViewImpl.cpp
+++ b/third_party/WebKit/Source/web/WebViewImpl.cpp
@@ -699,8 +699,8 @@
                             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;