Remove #pragma once from ash

ash/wm/workspace_controller_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 ASH_WM_WORKSPACE_CONTROLLER_TEST_HELPER_H_
 #define ASH_WM_WORKSPACE_CONTROLLER_TEST_HELPER_H_
-#pragma once
 
 #include "ash/wm/workspace_controller.h"
 
 namespace ash {
 namespace internal {
 
 class MultiWindowResizeController;
 class WorkspaceEventFilter;
 
 class WorkspaceControllerTestHelper {
  public:
   explicit WorkspaceControllerTestHelper(WorkspaceController* controller);
   ~WorkspaceControllerTestHelper();
 
   WorkspaceEventFilter* filter() { return controller_->event_filter_; }
   MultiWindowResizeController* GetMultiWindowResizeController();
 
  private:
   WorkspaceController* controller_;
 
   DISALLOW_COPY_AND_ASSIGN(WorkspaceControllerTestHelper);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_WORKSPACE_CONTROLLER_TEST_HELPER_H_