gpu: Refactor GpuMemoryBuffer framework for multi-process support.

gpu/command_buffer/client/gpu_memory_buffer.h

-// Copyright 2013 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 GPU_COMMAND_BUFFER_CLIENT_GPU_MEMORY_BUFFER_H_
-#define GPU_COMMAND_BUFFER_CLIENT_GPU_MEMORY_BUFFER_H_
-
-#include "base/basictypes.h"
-#include "base/memory/scoped_ptr.h"
-#include "gles2_impl_export.h"
-
-namespace gpu {
-
-// Interface for creating and accessing a zero-copy GPU memory buffer.
-// This design evolved from the generalization of GraphicBuffer API
-// of Android framework.
-//
-// THREADING CONSIDERATIONS:
-//
-// This interface is thread-safe. However, multiple threads mapping
-// a buffer for Write or ReadOrWrite simultaneously may result in undefined
-// behavior and is not allowed.
-class GLES2_IMPL_EXPORT GpuMemoryBuffer {
- public:
-  enum AccessMode {
-    READ_ONLY,
-    WRITE_ONLY,
-    READ_WRITE,
-  };
-
-  // Frees a previously allocated buffer. Freeing a buffer that is still
-  // mapped in any process is undefined behavior.
-  virtual ~GpuMemoryBuffer() {}
-
-  // Maps the buffer so the client can write the bitmap data in |*vaddr|
-  // subsequently. This call may block, for instance if the hardware needs
-  // to finish rendering or if CPU caches need to be synchronized.
-  virtual void Map(AccessMode mode, void** vaddr) = 0;
-
-  // Unmaps the buffer. Called after all changes to the buffer are
-  // completed.
-  virtual void Unmap() = 0;
-
-  // Returns true iff the buffer is mapped.
-  virtual bool IsMapped() = 0;
-
-  // Returns the native pointer for the buffer.
-  virtual void* GetNativeBuffer() = 0;
-
-  // Returns the stride in bytes for the buffer.
-  virtual uint32 GetStride() = 0;
-};
-
-}  // namespace gpu
-
-#endif  // GPU_COMMAND_BUFFER_CLIENT_GPU_MEMORY_BUFFER_H_