ozone: Implement zero/one-copy texture for Ozone GBM.

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"
@@ skipping 14 matching lines @@
 using GpuMemoryBufferId = int32;
 
 struct GFX_EXPORT GpuMemoryBufferHandle {
   GpuMemoryBufferHandle();
   bool is_null() const { return type == EMPTY_BUFFER; }
   GpuMemoryBufferType type;
   GpuMemoryBufferId id;
   base::SharedMemoryHandle handle;
 #if defined(OS_MACOSX)
   uint32 io_surface_id;
+#elif defined(USE_OZONE)
+  base::SharedMemoryHandle device_handle;

[reveman, 2015/05/11 16:40:56]

Please use |handle| instead.

[dshwang, 2015/05/14 12:25:47]

|handle| is used for prime fd, and |device_handle| is used for vgem fd.

[reveman, 2015/05/14 13:22:03]

Is the device_handle different for each buffer? If not, then I don't think it
belongs here.

[dshwang, 2015/05/14 14:58:15]

|device_handle| is kind of singleton. I'll make
(Child|Browser)GpuMemoryBufferManager keep vgem fd once to remove it in
GpuMemoryBufferHandle.

 #endif
 };
 
 // This interface typically correspond to a type of shared memory that is also
 // shared with the GPU. A GPU memory buffer can be written to directly by
 // regular CPU code, but can also be read by the GPU.
 class GFX_EXPORT GpuMemoryBuffer {
  public:
   // The format needs to be taken into account when mapping a buffer into the
   // client's address space.
@@ skipping 42 matching lines @@
   // Returns a platform specific handle for this buffer.
   virtual GpuMemoryBufferHandle GetHandle() const = 0;
 
   // Type-checking downcast routine.
   virtual ClientBuffer AsClientBuffer() = 0;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GPU_MEMORY_BUFFER_H_