Fix black background when locking with fullscreen window:

base/test/scoped_time_controller.cc

Index: base/test/scoped_time_controller.cc
diff --git a/base/test/scoped_time_controller.cc b/base/test/scoped_time_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..32aba03f9c40a68788990a2854c7e3e001b47ecd
--- /dev/null
+++ b/base/test/scoped_time_controller.cc
@@ -0,0 +1,37 @@
+// 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/logging.h"
+#include "base/test/scoped_time_controller.h"
+
+namespace base {
+namespace test {
+
+ScopedTimeController::ScopedTimeController()
+    : current_time_(Time::Now()),
+      current_timeticks_(TimeTicks::Now()) {
+  replaced_instance_ = TimeFactory::instance_;
+  TimeFactory::instance_ = this;
+}
+
+ScopedTimeController::~ScopedTimeController() {
+  TimeFactory::instance_ = replaced_instance_;
+}
+
+void ScopedTimeController::Advance(base::TimeDelta delta) {
+  DCHECK(delta >= base::TimeDelta());
+  current_time_ += delta;
+  current_timeticks_ += delta;
+}
+
+Time ScopedTimeController::TimeNow() {
+  return current_time_;
+}
+
+TimeTicks ScopedTimeController::TimeTicksNow() {
+  return current_timeticks_;
+}
+
+}  // namespace base
+}  // namespace test