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

ui/views/test/scoped_views_test_helper.cc

 // Copyright 2015 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/test/scoped_views_test_helper.h"
 
 #include <utility>
 
 #include "base/memory/ptr_util.h"
-#include "base/message_loop/message_loop.h"
 #include "ui/base/clipboard/clipboard.h"
 #include "ui/base/ime/input_method_initializer.h"
 #include "ui/base/test/test_clipboard.h"
 #include "ui/views/test/platform_test_helper.h"
 #include "ui/views/test/test_views_delegate.h"
 #include "ui/views/test/views_test_helper.h"
 
 namespace views {
 
 ScopedViewsTestHelper::ScopedViewsTestHelper()
     : ScopedViewsTestHelper(base::WrapUnique(new TestViewsDelegate)) {}
 
 ScopedViewsTestHelper::ScopedViewsTestHelper(
     std::unique_ptr<TestViewsDelegate> views_delegate)
     : test_views_delegate_(std::move(views_delegate)),
       platform_test_helper_(PlatformTestHelper::Create()) {
   // The ContextFactory must exist before any Compositors are created.
   ui::ContextFactory* context_factory = nullptr;
   ui::ContextFactoryPrivate* context_factory_private = nullptr;
   platform_test_helper_->InitializeContextFactory(&context_factory,
                                                   &context_factory_private);
 
   test_views_delegate_->set_context_factory(context_factory);
   test_views_delegate_->set_context_factory_private(context_factory_private);
 
-  test_helper_.reset(ViewsTestHelper::Create(base::MessageLoopForUI::current(),
-                                             context_factory,
-                                             context_factory_private));
+  test_helper_.reset(
+      ViewsTestHelper::Create(context_factory, context_factory_private));
   platform_test_helper_->OnTestHelperCreated(test_helper_.get());
   test_helper_->SetUp();
 
   ui::InitializeInputMethodForTesting();
   ui::TestClipboard::CreateForCurrentThread();
 }
 
 ScopedViewsTestHelper::~ScopedViewsTestHelper() {
   ui::Clipboard::DestroyClipboardForCurrentThread();
   ui::ShutdownInputMethodForTesting();
   test_helper_->TearDown();
   test_helper_.reset();
 
   test_views_delegate_.reset();
 
   // The Mus PlatformTestHelper has state that is deleted by
   // ui::TerminateContextFactoryForTests().
   platform_test_helper_.reset();
 }
 
 gfx::NativeWindow ScopedViewsTestHelper::GetContext() {
   return test_helper_->GetContext();
 }
 
 }  // namespace views