gpu: Add IOSurface backed GpuMemoryBuffer implementation.

ui/gfx/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 UI_GFX_GPU_MEMORY_BUFFER_H_
 #define UI_GFX_GPU_MEMORY_BUFFER_H_
 
 #include "base/memory/shared_memory.h"
 #include "build/build_config.h"
 #include "ui/gfx/gfx_export.h"
 
 #if defined(OS_ANDROID)
 #include <third_party/khronos/EGL/egl.h>
 #endif
 
 namespace gfx {
 
 enum GpuMemoryBufferType {
   EMPTY_BUFFER,
   SHARED_MEMORY_BUFFER,
-  EGL_CLIENT_BUFFER
+  EGL_CLIENT_BUFFER,
+  IO_SURFACE_BUFFER
 };
 
 struct GpuMemoryBufferHandle {
   GpuMemoryBufferHandle()
       : type(EMPTY_BUFFER),
         handle(base::SharedMemory::NULLHandle())
 #if defined(OS_ANDROID)
         , native_buffer(NULL)
 #endif
+#if defined(OS_MACOSX)
+        , io_surface_id(0)
+#endif
   {
   }
   bool is_null() const { return type == EMPTY_BUFFER; }
   GpuMemoryBufferType type;
   base::SharedMemoryHandle handle;
 #if defined(OS_ANDROID)
   EGLClientBuffer native_buffer;
 #endif
+#if defined(OS_MACOSX)
+  uint32 io_surface_id;
+#endif
+
 };
 
 // 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
@@ skipping 24 matching lines @@
   // Returns the stride in bytes for the buffer.
   virtual uint32 GetStride() const = 0;
 
   // Returns a platform specific handle for this buffer.
   virtual GpuMemoryBufferHandle GetHandle() const = 0;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GPU_MEMORY_BUFFER_H_