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

ui/views/test/views_test_helper_aura.cc

Index: ui/views/test/views_test_helper_aura.cc
diff --git a/ui/views/test/views_test_helper_aura.cc b/ui/views/test/views_test_helper_aura.cc
index 50196b58508987d1c3092fe8680b3e607479eadb..ba0f57ec547caeac2d71852a6d9731625fb566de 100644
--- a/ui/views/test/views_test_helper_aura.cc
+++ b/ui/views/test/views_test_helper_aura.cc
@@ -15,20 +15,17 @@ namespace views {
 
 // static
 ViewsTestHelper* ViewsTestHelper::Create(
-    base::MessageLoopForUI* message_loop,
     ui::ContextFactory* context_factory,
     ui::ContextFactoryPrivate* context_factory_private) {
-  return new ViewsTestHelperAura(message_loop, context_factory,
-                                 context_factory_private);
+  return new ViewsTestHelperAura(context_factory, context_factory_private);
 }
 
 ViewsTestHelperAura::ViewsTestHelperAura(
-    base::MessageLoopForUI* message_loop,
     ui::ContextFactory* context_factory,
     ui::ContextFactoryPrivate* context_factory_private)
     : context_factory_(context_factory),
       context_factory_private_(context_factory_private) {
-  aura_test_helper_.reset(new aura::test::AuraTestHelper(message_loop));
+  aura_test_helper_.reset(new aura::test::AuraTestHelper());
 }
 
 ViewsTestHelperAura::~ViewsTestHelperAura() {