content: Cleanup GpuMemoryBuffer allocation.

content/common/gpu/client/gpu_memory_buffer_impl.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 CONTENT_COMMON_GPU_CLIENT_GPU_MEMORY_BUFFER_IMPL_H_
 #define CONTENT_COMMON_GPU_CLIENT_GPU_MEMORY_BUFFER_IMPL_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "ui/gfx/gpu_memory_buffer.h"
 #include "ui/gfx/size.h"
 
 namespace content {
 
 // Provides common implementation of a GPU memory buffer.
 class GpuMemoryBufferImpl : public gfx::GpuMemoryBuffer {
  public:
-  static scoped_ptr<GpuMemoryBufferImpl> Create(
+  virtual ~GpuMemoryBufferImpl();
+
+  // Creates a GPU memory buffer instance with |size| and |internalformat|.
+  static scoped_ptr<GpuMemoryBufferImpl> Create(const gfx::Size& size,
+                                                unsigned internalformat);
+
+  // Allocates a GPU memory buffer with |size| and |internalformat| for use by
+  // |child_process|. The |handle| returned can be used by the |child_process|
+  // to create an instance of this class.
+  static void AllocateForChildProcess(const gfx::Size& size,
+                                      unsigned internalformat,
+                                      base::ProcessHandle child_process,
+                                      gfx::GpuMemoryBufferHandle* handle);
+
+  // Creates an instance from the given |handle|. |size| and |internalformat|
+  // should match what was used to allocate the |handle|.
+  static scoped_ptr<GpuMemoryBufferImpl> CreateFromHandle(
       gfx::GpuMemoryBufferHandle handle,
-      gfx::Size size,
+      const gfx::Size& size,
       unsigned internalformat);
 
-  virtual ~GpuMemoryBufferImpl();
+  // Returns true if |internalformat| is a format recognized by this base class.
+  static bool IsFormatValid(unsigned internalformat);
 
-  static bool IsFormatValid(unsigned internalformat);
+  // Returns the number of bytes per pixel that must be used by an
+  // implementation when using |internalformat|.
   static size_t BytesPerPixel(unsigned internalformat);
 
   // Overridden from gfx::GpuMemoryBuffer:
   virtual bool IsMapped() const OVERRIDE;
   virtual uint32 GetStride() const OVERRIDE;
 
  protected:
-  GpuMemoryBufferImpl(gfx::Size size, unsigned internalformat);
+  GpuMemoryBufferImpl(const gfx::Size& size, unsigned internalformat);
 
   const gfx::Size size_;
-  unsigned internalformat_;
+  const unsigned internalformat_;
   bool mapped_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuMemoryBufferImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_GPU_MEMORY_BUFFER_IMPL_H_