Fix black background when locking with fullscreen window:

ui/base/animation/animation_container_test_helper.cc

Index: ui/base/animation/animation_container_test_helper.cc
diff --git a/ui/base/animation/animation_container_test_helper.cc b/ui/base/animation/animation_container_test_helper.cc
new file mode 100644
index 0000000000000000000000000000000000000000..673e97cc1467e91eaab961d949b0c805f587933f
--- /dev/null
+++ b/ui/base/animation/animation_container_test_helper.cc
@@ -0,0 +1,40 @@
+// Copyright (c) 2011 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 "ui/base/animation/animation_container_test_helper.h"
+
+using base::TimeDelta;
+using base::TimeTicks;
+
+namespace ui {
+namespace test {
+
+AnimationContainerTestHelper::AnimationContainerTestHelper(
+    AnimationContainer* container)
+    : container_(container),
+      time_controller_(new base::test::ScopedTimeController()) {
+}
+
+void AnimationContainerTestHelper::Advance(TimeDelta delta) {
+  time_controller_->Advance(delta);
+  if (IsAnimating())
+    container_->Run();
+}
+
+void AnimationContainerTestHelper::Ping() {
+  if (IsAnimating())
+    container_->Run();
+}
+
+void AnimationContainerTestHelper::AdvanceWhileRunning() {
+  while (IsAnimating())
+    Advance(TimeDelta::FromSeconds(1));
+}
+
+bool AnimationContainerTestHelper::IsAnimating() {
+  return container_->timer_.IsRunning();
+}
+
+}  // namespace test
+}  // namespace ui