Fix black background when locking with fullscreen window:

base/test/scoped_time_controller.cc

+// 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 "base/test/scoped_time_controller.h"
+
+namespace base {
+namespace test {
+
+ScopedTimeController::ScopedTimeController() {
+  replaced_instance_ = TimeFactory::instance_;
+  TimeFactory::instance_ = this;
+}
+
+ScopedTimeController::~ScopedTimeController() {
+  TimeFactory::instance_ = replaced_instance_;
+}
+
+void ScopedTimeController::Advance(base::TimeDelta delta) {
+  current_time_ += delta;
+  current_timeticks_ += delta;
+}
+
+Time ScopedTimeController::TimeNow() {
+  return current_time_;
+}
+
+TimeTicks ScopedTimeController::TimeTicksNow() {
+  return current_timeticks_;
+}
+
+TimeTicks ScopedTimeController::TimeTicksHighResNow() {
+  return current_timeticks_;
+}
+
+}  // namespace base
+}  // namespace test