Use ScopedTaskEnvironment instead of MessageLoopForUI in ViewsTestBase.

ui/views/widget/desktop_aura/desktop_native_widget_aura_unittest.cc

 // Copyright 2013 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/views/widget/desktop_aura/desktop_native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/single_thread_task_runner.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/cursor_client.h"
 #include "ui/aura/client/window_parenting_client.h"
 #include "ui/aura/test/test_window_delegate.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
 #include "ui/display/screen.h"
 #include "ui/events/event_processor.h"
 #include "ui/events/event_utils.h"
@@ skipping 229 matching lines @@
   params.ownership = Widget::InitParams::WIDGET_OWNS_NATIVE_WIDGET;
   params.native_widget = new DesktopNativeWidgetAura(widget.get());
   widget->Init(params);
   widget->Show();
 
   // Post a task that terminates the nested loop and destroyes the widget. This
   // task will be executed from the nested loop initiated with the call to
   // |RunWithDispatcher()| below.
   base::RunLoop run_loop;
   base::Closure quit_runloop = run_loop.QuitClosure();
-  message_loop()->task_runner()->PostTask(
+  base::ThreadTaskRunnerHandle::Get()->PostTask(
       FROM_HERE,
       base::Bind(&QuitNestedLoopAndCloseWidget, base::Passed(&widget),
                  base::Unretained(&quit_runloop)));
   run_loop.Run();
 }
 
 // This class provides functionality to create fullscreen and top level popup
 // windows. It additionally tests whether the destruction of these windows
 // occurs correctly in desktop AURA without crashing.
 // It provides facilities to test the following cases:-
@@ skipping 405 matching lines @@
   target->HandleKeyboardMessage(WM_CHAR, 0, 0, &handled);
   target->HandleKeyboardMessage(WM_SYSCHAR, 0, 0, &handled);
   target->HandleKeyboardMessage(WM_SYSDEADCHAR, 0, 0, &handled);
   widget.CloseNow();
 }
 
 #endif  // defined(OS_WIN)
 
 }  // namespace test
 }  // namespace views