Add GrabWindowSnapshotAsync tests

ui/aura/test/aura_test_helper.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 "ui/aura/test/aura_test_helper.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/aura_constants.h"
 #include "ui/aura/client/default_activation_client.h"
@@ skipping 44 matching lines @@
 #endif
 }
 
 AuraTestHelper::~AuraTestHelper() {
   CHECK(setup_called_)
       << "AuraTestHelper::SetUp() never called.";
   CHECK(teardown_called_)
       << "AuraTestHelper::TearDown() never called.";
 }
 
-void AuraTestHelper::SetUp() {
+void AuraTestHelper::SetUp(bool allow_test_contexts) {
   setup_called_ = true;
 
   // The ContextFactory must exist before any Compositors are created.
-  bool allow_test_contexts = true;
   ui::InitializeContextFactoryForTests(allow_test_contexts);
 
   Env::CreateInstance();
   // Unit tests generally don't want to query the system, rather use the state
   // from RootWindow.
   EnvTestHelper(Env::GetInstance()).SetInputStateLookup(
       scoped_ptr<InputStateLookup>());
 
   ui::InitializeInputMethodForTesting();
 
@@ skipping 42 matching lines @@
 
 void AuraTestHelper::RunAllPendingInMessageLoop() {
   // TODO(jbates) crbug.com/134753 Find quitters of this RunLoop and have them
   //              use run_loop.QuitClosure().
   base::RunLoop run_loop(Env::GetInstance()->GetDispatcher());
   run_loop.RunUntilIdle();
 }
 
 }  // namespace test
 }  // namespace aura