[ozone] clang warning fix for https://codereview.chromium.org/905873003

ui/ozone/platform/dri/dri_gpu_platform_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 UI_OZONE_PLATFORM_DRI_DRI_GPU_PLATFORM_SUPPORT_H_
 #define UI_OZONE_PLATFORM_DRI_DRI_GPU_PLATFORM_SUPPORT_H_
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "ipc/message_filter.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/ozone/public/gpu_platform_support.h"
 
 class SkBitmap;
 
 namespace base {
-class FileDescriptor;
 class FilePath;
 class SingleThreadTaskRunner;
+struct FileDescriptor;
 }
 
 namespace gfx {
 class Point;
 class Rect;
 }
 
 namespace ui {
 
 class DriSurfaceFactory;
@@ skipping 57 matching lines @@
   ScreenManager* screen_manager_;             // Not owned.
 
   scoped_ptr<NativeDisplayDelegateDri> ndd_;
   ScopedVector<GpuPlatformSupport> handlers_;
   scoped_refptr<IPC::MessageFilter> filter_;
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_DRI_GPU_PLATFORM_SUPPORT_H_