Add FadeOut delay animation to MouseLeave

cc/input/scrollbar_animation_controller.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/input/scrollbar_animation_controller.h"
 
 #include <algorithm>
 
 #include "base/time/time.h"
 #include "cc/trees/layer_tree_impl.h"
@@ skipping 107 matching lines @@
   if (!mouse_is_near_any_scrollbar())
     PostDelayedAnimationTask(false);
 }
 
 void ScrollbarAnimationController::DidMouseLeave() {
   if (!NeedThinningAnimation())
     return;
 
   vertical_controller_->DidMouseLeave();
   horizontal_controller_->DidMouseLeave();
+
+  if (ScrollbarsHidden() || Captured())
+    return;
+
+  PostDelayedAnimationTask(false);
 }
 
 void ScrollbarAnimationController::DidMouseMoveNear(
     ScrollbarOrientation orientation,
     float distance) {
   if (!NeedThinningAnimation())
     return;
 
   GetScrollbarAnimationController(orientation).DidMouseMoveNear(distance);
 
@@ skipping 57 matching lines @@
   return client_->ScrollbarsFor(scroll_layer_id_);
 }
 
 void ScrollbarAnimationController::set_mouse_move_distance_for_test(
     float distance) {
   vertical_controller_->set_mouse_move_distance_for_test(distance);
   horizontal_controller_->set_mouse_move_distance_for_test(distance);
 }
 
 }  // namespace cc