Provide real GPUSupport to ash for Chrome

ash/gpu_support.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 ASH_GPU_SUPPORT_H_
 #define ASH_GPU_SUPPORT_H_
 
 #include <list>
 
+#include "ash/ash_export.h"
 #include "base/callback_forward.h"
 #include "base/process/process.h"
 
 namespace ash {
 
 // An interface to allow use of content::GpuDataManager to be injected in
 // configurations that permit a dependency on content.
-class GPUSupport {
+class ASH_EXPORT GPUSupport {
  public:
   typedef base::Callback<void(const std::list<base::ProcessHandle>&)>
       GetGpuProcessHandlesCallback;
 
   virtual ~GPUSupport() {}
 
   virtual bool IsPanelFittingDisabled() const = 0;
 
   virtual void DisableGpuWatchdog() = 0;
 
   virtual void GetGpuProcessHandles(
       const GetGpuProcessHandlesCallback& callback) const = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_GPU_SUPPORT_H_