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

ui/ozone/platform/dri/native_display_delegate_dri.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_NATIVE_DISPLAY_DELEGATE_DRI_H_
 #define UI_OZONE_PLATFORM_DRI_NATIVE_DISPLAY_DELEGATE_DRI_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "ui/ozone/common/gpu/ozone_gpu_message_params.h"
 
 namespace base {
-class FileDescriptor;
 class FilePath;
 class SingleThreadTaskRunner;
+struct FileDescriptor;
 }
 
 namespace ui {
 
 class DeviceManager;
 class DisplaySnapshotDri;
 class DisplayMode;
 class DisplayModeDri;
 class DriWrapper;
 class DrmDeviceGenerator;
@@ skipping 57 matching lines @@
   // of them independently for cleanup.
   ScopedVector<const DisplayMode> cached_modes_;
   ScopedVector<DisplaySnapshotDri> cached_displays_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeDisplayDelegateDri);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PLATFORM_DRI_NATIVE_DISPLAY_DELEGATE_DRI_H_