[Mojo Video Capture] Move SharedMem Tracker/BufferHandle/Factory from content to media

content/browser/renderer_host/media/shared_memory_buffer_tracker.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 CONTENT_BROWSER_RENDERER_HOST_MEDIA_SHARED_MEMORY_BUFFER_TRACKER_H_
-#define CONTENT_BROWSER_RENDERER_HOST_MEDIA_SHARED_MEMORY_BUFFER_TRACKER_H_
-
-#include "media/capture/video/video_capture_buffer_tracker.h"
-
-namespace content {
-
-// Tracker specifics for SharedMemory.
-class SharedMemoryBufferTracker final
-    : public media::VideoCaptureBufferTracker {
- public:
-  SharedMemoryBufferTracker();
-
-  bool Init(const gfx::Size& dimensions,
-            media::VideoPixelFormat format,
-            media::VideoPixelStorage storage_type,
-            base::Lock* lock) override;
-
-  std::unique_ptr<media::VideoCaptureBufferHandle> GetBufferHandle() override;
-  mojo::ScopedSharedBufferHandle GetHandleForTransit() override;
-
- private:
-  friend class SharedMemoryBufferHandle;
-
-  // The memory created to be shared with renderer processes.
-  base::SharedMemory shared_memory_;
-  size_t mapped_size_;
-};
-
-
-}  // namespace content
-
-#endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_SHARED_MEMORY_BUFFER_TRACKER_H_