Add NativePixmapHandle type & interface for exporting them

ui/ozone/public/native_pixmap.h

 // Copyright 2014 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_OZONE_PUBLIC_NATIVE_PIXMAP_H_
 #define UI_OZONE_PUBLIC_NATIVE_PIXMAP_H_
 
 #include "base/bind.h"
 #include "base/memory/ref_counted.h"
+#include "ui/gfx/native_pixmap_handle_ozone.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gfx/overlay_transform.h"
 
 namespace gfx {
 class Rect;
 class RectF;
 }
 
 namespace ui {
 
@@ skipping 26 matching lines @@
 
   // This represents a callback function pointing to scaling unit like VPP
   // to do scaling operations on native pixmap with required size.
   typedef base::Callback<scoped_refptr<NativePixmap>(gfx::Size)>
       ScalingCallback;
 
   // Set callback function for the pixmap used for scaling.
   virtual void SetScalingCallback(const ScalingCallback& scaling_callback) = 0;
   virtual scoped_refptr<NativePixmap> GetScaledPixmap(gfx::Size new_size) = 0;
 
+  // Export the buffer for sharing across processes.
+  // Any file descriptors in the exported handle are owned by the caller.
+  virtual gfx::NativePixmapHandle ExportHandle() = 0;
+
  protected:
   virtual ~NativePixmap() {}
 
  private:
   friend class base::RefCountedThreadSafe<NativePixmap>;
 
   DISALLOW_COPY_AND_ASSIGN(NativePixmap);
 };
 
 }  // namespace ui
 
 #endif  // UI_OZONE_PUBLIC_NATIVE_PIXMAP_H_