Migrate content/common/gpu/media code to media/gpu

content/common/gpu/media/shared_memory_region.h

-// Copyright (c) 2015 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_COMMON_GPU_MEDIA_SHARED_MEMORY_REGION_H_
-#define CONTENT_COMMON_GPU_MEDIA_SHARED_MEMORY_REGION_H_
-
-#include "base/memory/shared_memory.h"
-#include "media/base/bitstream_buffer.h"
-
-namespace content {
-
-// Helper class to access a region of a SharedMemory. Different from
-// SharedMemory, in which the |offset| of function MapAt() must be aligned to
-// the value of |SysInfo::VMAllocationGranularity()|, the |offset| of a
-// SharedMemoryRegion needs not to be aligned, this class hides the details
-// and returns the mapped address of the given offset.
-class SharedMemoryRegion {
- public:
-  // Creates a SharedMemoryRegion.
-  // The mapped memory region begins at |offset| bytes from the start of the
-  // shared memory and the length is |size|. It will take the ownership of
-  // the |handle| and release the resource when being destroyed. Different
-  // from SharedMemory, the |offset| needs not to be aligned to the value of
-  // |SysInfo::VMAllocationGranularity()|.
-  SharedMemoryRegion(const base::SharedMemoryHandle& handle,
-                     off_t offset,
-                     size_t size,
-                     bool read_only);
-
-  // Creates a SharedMemoryRegion from the given |bistream_buffer|.
-  SharedMemoryRegion(const media::BitstreamBuffer& bitstream_buffer,
-                     bool read_only);
-
-  // Maps the shared memory into the caller's address space.
-  // Return true on success, false otherwise.
-  bool Map();
-
-  // Gets a pointer to the mapped region if it has been mapped via Map().
-  // Returns |nullptr| if it is not mapped. The returned pointer points
-  // to the memory at the offset previously passed to the constructor.
-  void* memory();
-
-  size_t size() const { return size_; }
-
- private:
-  base::SharedMemory shm_;
-  off_t offset_;
-  size_t size_;
-  size_t alignment_size_;
-
-  DISALLOW_COPY_AND_ASSIGN(SharedMemoryRegion);
-};
-
-}  // namespace content
-
-#endif  // CONTENT_COMMON_GPU_MEDIA_SHARED_MEMORY_REGION_H_