Fix black background when locking with fullscreen window:

ui/base/animation/animation_container_test_helper.h

Index: ui/base/animation/animation_container_test_helper.h
diff --git a/ui/base/animation/animation_container_test_helper.h b/ui/base/animation/animation_container_test_helper.h
new file mode 100644
index 0000000000000000000000000000000000000000..fd833de4f3a43c71c9fe08d00a66a06b2a6429f1
--- /dev/null
+++ b/ui/base/animation/animation_container_test_helper.h
@@ -0,0 +1,52 @@
+// 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.
+
+#ifndef UI_BASE_ANIMATION_ANIMATION_CONTAINER_TEST_HELPER_H_
+#define UI_BASE_ANIMATION_ANIMATION_CONTAINER_TEST_HELPER_H_
+
+#include "base/test/scoped_time_controller.h"
+#include "base/time.h"
+#include "ui/base/animation/animation_container.h"
+#include "ui/base/ui_export.h"
+
+namespace ui {
+namespace test {
+
+// This class can be used in tests for fine control over animations.
+
+class UI_EXPORT AnimationContainerTestHelper {
+ public:
+  // Creates helper for given container. Container is now driven by this
+  // helper rather than by internal timer.
+  explicit AnimationContainerTestHelper(AnimationContainer* container);
+  virtual ~AnimationContainerTestHelper() {};

[sky, 2012/12/10 22:20:16]

Why the virtual? And don't inline and remove ;

[Denis Kuznetsov (DE-MUC), 2012/12/11 13:27:57]

So that there are no warnings if it is used with scoped_ptr.
Done.

[sky, 2012/12/11 16:44:17]

scoped_ptr shouldn't require a virtual destructor. What error do you see when
the destructor is not virtual?

+
+  // Advances AnimationContainer for |delta|.
+  void Advance(base::TimeDelta delta);
+
+  // Returns if AnimationContainer is animating.
+  bool IsAnimating();
+
+  // Forwards in large steps (1 second) while there are any animations running.
+  // Use it before deleting Helper to avoid negative time delta in animations
+  // once timer gets cleaned up.
+  void AdvanceWhileRunning();

[sky, 2012/12/10 22:20:16]

How about AdvanceUntilDone.

[Denis Kuznetsov (DE-MUC), 2012/12/11 13:27:57]

Done.

+
+  // Calls Run method of Container without advancing time. Call this method once
+  // some animations were added to container so that any immediate animations
+  // get processed.
+  void Ping();

[sky, 2012/12/10 22:20:16]

Is there a reason this is needed instead of Advance(0)?

[Denis Kuznetsov (DE-MUC), 2012/12/11 13:27:57]

Done.

+
+ private:
+  AnimationContainer* container_;
+
+  scoped_ptr<base::test::ScopedTimeController> time_controller_;

[sky, 2012/12/10 22:20:16]

Declare this by value (eg not in a scoped_ptr).

[Denis Kuznetsov (DE-MUC), 2012/12/11 13:27:57]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(AnimationContainerTestHelper);
+};
+
+}  // namespace test
+}  // namespace ui
+
+#endif  // UI_BASE_ANIMATION_ANIMATION_CONTAINER_TEST_HELPER_H_