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

content/browser/renderer_host/media/shared_memory_buffer_handle.cc

-// 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.
-
-#include "content/browser/renderer_host/media/shared_memory_buffer_handle.h"
-
-#include "content/browser/renderer_host/media/shared_memory_buffer_tracker.h"
-
-namespace content {
-
-SharedMemoryBufferHandle::SharedMemoryBufferHandle(
-    SharedMemoryBufferTracker* tracker)
-    : tracker_(tracker) {}
-
-SharedMemoryBufferHandle::~SharedMemoryBufferHandle() = default;
-
-gfx::Size SharedMemoryBufferHandle::dimensions() const {
-  return tracker_->dimensions();
-}
-
-size_t SharedMemoryBufferHandle::mapped_size() const {
-  return tracker_->mapped_size_;
-}
-
-void* SharedMemoryBufferHandle::data(int plane) {
-  DCHECK_EQ(plane, 0);
-  return tracker_->shared_memory_.memory();
-}
-
-#if defined(OS_POSIX) && !defined(OS_MACOSX)
-base::FileDescriptor SharedMemoryBufferHandle::AsPlatformFile() {
-  return tracker_->shared_memory_.handle();
-}
-#endif
-
-bool SharedMemoryBufferHandle::IsBackedByVideoFrame() const {
-  return false;
-}
-
-scoped_refptr<media::VideoFrame> SharedMemoryBufferHandle::GetVideoFrame() {
-  return scoped_refptr<media::VideoFrame>();
-}
-
-}  // namespace content