Add NativePixmapHandle type & interface for exporting them

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 "base/trace_event/memory_dump_manager.h"
 #include "build/build_config.h"
 #include "ui/gfx/buffer_types.h"
 #include "ui/gfx/gfx_export.h"
 
+#if defined(USE_OZONE)
+#include "ui/gfx/native_pixmap_handle_ozone.h"
+#endif
+
 extern "C" typedef struct _ClientBuffer* ClientBuffer;
 
 namespace gfx {
 
 enum GpuMemoryBufferType {
   EMPTY_BUFFER,
   SHARED_MEMORY_BUFFER,
   IO_SURFACE_BUFFER,
   SURFACE_TEXTURE_BUFFER,
   OZONE_NATIVE_PIXMAP,
   GPU_MEMORY_BUFFER_TYPE_LAST = OZONE_NATIVE_PIXMAP
 };
 
 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(USE_OZONE)
+  NativePixmapHandle native_pixmap_handle;

[dshwang, 2015/08/05 13:30:10]

we can pass |dmabuf_fd| via GpuMemoryBufferHandle::handle, but use
NativePixmapHandle::fd instead. GpuMemoryBufferHandle::handle is not used in
ozone.
So additional member is |stride|. I'm not sure if we will add additional
metadata. imho, it looks over-generalized.

[reveman, 2015/08/05 13:58:52]

I prefer having the fd as part of |native_pixmap_handle|.

[dshwang, 2015/08/05 14:12:51]

I see. lgtm

+#endif
 };
 
 base::trace_event::MemoryAllocatorDumpGuid GFX_EXPORT
 GetGpuMemoryBufferGUIDForTracing(uint64 tracing_process_id,
                                  GpuMemoryBufferId buffer_id);
 
 // 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 {
@@ skipping 27 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_