gpu: Add GpuMemoryBufferFactory interface.

gpu/command_buffer/client/gpu_memory_buffer_factory.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_FACTORY_BUFFER_H_
+#define GPU_COMMAND_BUFFER_CLIENT_GPU_MEMORY_FACTORY_BUFFER_H_
+
+#include "gpu/gpu_export.h"
+
+namespace gpu {
+class GpuMemoryBuffer;
+
+class GPU_EXPORT GpuMemoryBufferFactory {
+ public:
+  virtual gpu::GpuMemoryBuffer* CreateGpuMemoryBuffer(

[joth, 2013/07/26 05:28:05]

Out of interest why does this need to be a factory now? In previous review we
had it as factory but were told as it was only one method it is preferable to
use callback.

As base::Bind() supports currying and attachment to member functions, you can
have a stateful factory with either approach.

[reveman, 2013/07/26 15:40:57]

This will replace the ImageFactory interface and be passed to the
CommandBufferService in follow up patches. base::Bind() does ref-counting
internally so it's not appropriate for storing in a global variable. We could
just use a raw function pointer as before but I strongly prefer a real interface
as it makes usage clearer and makes it easy to add a DestroyGpuMemoryBuffer
function which is likely needed to keep things clean when adding future buffer
types.

+      size_t width,
+      size_t height,
+      unsigned internalformat) = 0;
+
+ protected:
+  virtual ~GpuMemoryBufferFactory() {}
+};
+
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_CLIENT_GPU_MEMORY_BUFFER_FACTORY_H_