Fixes three crashes

athena/test/athena_test_helper.h

 // Copyright 2014 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 ATHENA_TEST_ATHENA_TEST_HELPER_H_
 #define ATHENA_TEST_ATHENA_TEST_HELPER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/aura/window_tree_host.h"
 
 namespace base {
 class MessageLoopForUI;
+class Thread;
 }
 
 namespace ui {
 class ContextFactory;
 class ScopedAnimationDurationScaleMode;
 }
 
 namespace aura {
 class Window;
 class TestScreen;
@@ skipping 37 matching lines @@
   bool teardown_called_;
 
   base::MessageLoopForUI* message_loop_;
 
   scoped_ptr<aura::WindowTreeHost> host_;
   scoped_ptr<aura::TestScreen> test_screen_;
   scoped_ptr<TestScreenManagerDelegate> screen_manager_delegate_;
   scoped_ptr<aura::client::FocusClient> focus_client_;
   scoped_ptr< ::wm::InputMethodEventFilter> input_method_filter_;
   scoped_ptr<ui::ScopedAnimationDurationScaleMode> zero_duration_mode_;
+  scoped_ptr<base::Thread> file_thread_;
 
   DISALLOW_COPY_AND_ASSIGN(AthenaTestHelper);
 };
 
 }  // namespace test
 }  // namespace athena
 
 #endif  // ATHENA_TEST_ATHENA_TEST_HELPER_H_