Use ScopedTaskEnvironment instead of MessageLoopForUI in ui/aura/test/.

ui/aura/test/aura_test_base.h

 // Copyright (c) 2012 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_AURA_TEST_AURA_TEST_BASE_H_
 #define UI_AURA_TEST_AURA_TEST_BASE_H_
 
 #include <memory>
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/aura/mus/property_converter.h"
 #include "ui/aura/mus/window_manager_delegate.h"
 #include "ui/aura/mus/window_tree_client_delegate.h"
 #include "ui/aura/test/aura_test_helper.h"
 
 namespace ui {
 namespace mojom {
 class WindowTreeClient;
 }
@@ skipping 109 matching lines @@
   void OnWmCancelMoveLoop(Window* window) override;
   void OnWmSetClientArea(
       Window* window,
       const gfx::Insets& insets,
       const std::vector<gfx::Rect>& additional_client_areas) override;
   bool IsWindowActive(aura::Window* window) override;
   void OnWmDeactivateWindow(Window* window) override;
   PropertyConverter* GetPropertyConverter() override;
 
  private:
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
+
   // Only used for mus. Both are are initialized to this, but may be reset.
   WindowManagerDelegate* window_manager_delegate_;
   WindowTreeClientDelegate* window_tree_client_delegate_;
 
   bool use_mus_ = false;
   bool setup_called_ = false;
   bool teardown_called_ = false;
-  base::MessageLoopForUI message_loop_;
   PropertyConverter property_converter_;
   std::unique_ptr<AuraTestHelper> helper_;
   std::vector<std::unique_ptr<WindowTreeHostMus>> window_tree_hosts_;
 
   DISALLOW_COPY_AND_ASSIGN(AuraTestBase);
 };
 
 // Use as a base class for tests that want to target both backends.
 class AuraTestBaseWithType : public AuraTestBase,
                              public ::testing::WithParamInterface<BackendType> {
@@ skipping 19 matching lines @@
   void SetUp() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(AuraTestBaseMus);
 };
 
 }  // namespace test
 }  // namespace aura
 
 #endif  // UI_AURA_TEST_AURA_TEST_BASE_H_