Revert of [Mojo Video Capture] Simplify media::VideoCaptureDevice::Client:Buffer to a struct

services/video_capture/buffer_tracker_factory_impl.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 SERVICES_VIDEO_CAPTURE_BUFFER_TRACKER_FACTORY_IMPL_H_
+#define SERVICES_VIDEO_CAPTURE_BUFFER_TRACKER_FACTORY_IMPL_H_
+
+#include <memory>
+
+#include "media/capture/video/video_capture_buffer_tracker_factory.h"
+
+namespace video_capture {
+
+// Implementation of media::VideoCaptureBufferTrackerFactory specific to the
+// Mojo Video Capture service. It produces buffers that are backed by
+// mojo shared memory.
+class BufferTrackerFactoryImpl
+    : public media::VideoCaptureBufferTrackerFactory {
+ public:
+  std::unique_ptr<media::VideoCaptureBufferTracker> CreateTracker(
+      media::VideoPixelStorage storage) override;
+};
+
+}  // namespace video_capture
+
+#endif  // SERVICES_VIDEO_CAPTURE_BUFFER_TRACKER_FACTORY_IMPL_H_