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

content/browser/renderer_host/render_widget_host_view_aura_unittest.cc

 // 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <tuple>
@@ skipping 582 matching lines @@
       RenderWidgetHostViewAura* render_widget_host_view,
       std::unique_ptr<DelegatedFrameHostClient> delegated_frame_host_client) {
     render_widget_host_view->delegated_frame_host_client_ =
         std::move(delegated_frame_host_client);
   }
 
   void SetUpEnvironment() {
     ImageTransportFactory::InitializeForUnitTests(
         std::unique_ptr<ImageTransportFactory>(
             new NoTransportImageTransportFactory));
-    aura_test_helper_.reset(
-        new aura::test::AuraTestHelper(base::MessageLoopForUI::current()));
+    aura_test_helper_.reset(new aura::test::AuraTestHelper());
     aura_test_helper_->SetUp(
         ImageTransportFactory::GetInstance()->GetContextFactory(),
         ImageTransportFactory::GetInstance()->GetContextFactoryPrivate());
     new wm::DefaultActivationClient(aura_test_helper_->root_window());
 
     browser_context_.reset(new TestBrowserContext);
     process_host_ = new MockRenderProcessHost(browser_context_.get());
     process_host_->Init();
 
     sink_ = &process_host_->sink();
@@ skipping 4878 matching lines @@
     // There is no composition in the beginning.
     EXPECT_FALSE(has_composition_text());
     SetHasCompositionTextToTrue();
     view->ImeCancelComposition();
     // The composition must have been canceled.
     EXPECT_FALSE(has_composition_text());
   }
 }
 
 }  // namespace content