Add GrabWindowSnapshotAsync tests

ui/aura/test/aura_test_helper.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_HELPER_H_
 #define UI_AURA_TEST_AURA_TEST_HELPER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/root_window.h"
@@ skipping 23 matching lines @@
 
 // A helper class owned by tests that does common initialization required for
 // Aura use. This class creates a root window with clients and other objects
 // that are necessary to run test on Aura.
 class AuraTestHelper {
  public:
   explicit AuraTestHelper(base::MessageLoopForUI* message_loop);
   ~AuraTestHelper();
 
   // Creates and initializes (shows and sizes) the RootWindow for use in tests.
-  void SetUp();
+  void SetUp(bool allow_test_contexts);
 
   // Clean up objects that are created for tests. This also deletes the Env
   // object.
   void TearDown();
 
   // Flushes message loop.
   void RunAllPendingInMessageLoop();
 
   Window* root_window() { return root_window_->window(); }
   RootWindow* dispatcher() { return root_window_.get(); }
@@ skipping 18 matching lines @@
   scoped_ptr<gfx::SurfaceFactoryOzone> surface_factory_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(AuraTestHelper);
 };
 
 }  // namespace test
 }  // namespace aura
 
 #endif  // UI_AURA_TEST_AURA_TEST_HELPER_H_