Revert "Implement GpuArcVideoService for arc video accelerator"

components/arc/video/video_host_delegate.h

-// Copyright 2016 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 COMPONENTS_ARC_VIDEO_VIDEO_HOST_DELEGATE_H
-#define COMPONENTS_ARC_VIDEO_VIDEO_HOST_DELEGATE_H
-
-#include "components/arc/common/video.mojom.h"
-
-namespace arc {
-
-// VideoHostDelegate is an abstract class providing video decoding/encoding
-// acceleration service.
-//
-// The purpose of this interface is to create a channel into the GPU process
-// only, which then handles video decoding/encoding, without going through
-// VideoHostDelegate anymore.
-class VideoHostDelegate : public VideoHost {
- public:
-  // Called when the video service is stopping.
-  virtual void OnStopping() = 0;
-};
-
-}  // namespace arc
-
-#endif  // COMPONENTS_ARC_VIDEO_VIDEO_HOST_DELEGATE_H