Add NativePixmapHandle type & interface for exporting them

ui/gfx/gfx.gyp

 # Copyright (c) 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 199 matching lines @@
         'ios/NSString+CrStringDrawing.mm',
         'ios/uikit_util.h',
         'ios/uikit_util.mm',
         'linux_font_delegate.cc',
         'linux_font_delegate.h',
         'mac/coordinate_conversion.h',
         'mac/coordinate_conversion.mm',
         'mac/nswindow_frame_controls.h',
         'mac/nswindow_frame_controls.mm',
         'mac/scoped_cocoa_disable_screen_updates.h',
+        'native_pixmap_handle_ozone.h',
         'native_widget_types.h',
         'nine_image_painter.cc',
         'nine_image_painter.h',
         'overlay_transform.h',
         'paint_throbber.cc',
         'paint_throbber.h',
         'path.cc',
         'path.h',
         'path_win.cc',
         'path_win.h',
@@ skipping 320 matching lines @@
          ],
          'variables': {
            'jni_gen_package': 'ui/gfx',
          },
          'includes': [ '../../build/jni_generator.gypi' ],
        },
      ],
     }],
   ],
 }