Turn on canvas_skia for OSX

ui/ui.gyp

 # Copyright (c) 2012 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,
   },
   'includes': [
     'shell_dialogs.gypi',
@@ skipping 401 matching lines @@
         'gfx/android/java_bitmap.cc',
         'gfx/android/java_bitmap.h',
         'gfx/blit.cc',
         'gfx/blit.h',
         'gfx/box_f.cc',
         'gfx/box_f.h',
         'gfx/break_list.h',
         'gfx/canvas.cc',
         'gfx/canvas.h',
         'gfx/canvas_android.cc',
-        'gfx/canvas_mac.mm',
         'gfx/canvas_paint_gtk.cc',
         'gfx/canvas_paint_gtk.h',
         'gfx/canvas_paint_mac.h',
         'gfx/canvas_paint_mac.mm',
         'gfx/canvas_paint_win.cc',
         'gfx/canvas_paint_win.h',
         'gfx/canvas_skia.cc',
         'gfx/canvas_skia_paint.h',
         'gfx/codec/jpeg_codec.cc',
         'gfx/codec/jpeg_codec.h',
@@ skipping 206 matching lines @@
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/CoreGraphics.framework',
             ],
           },
         }],
         # TODO(asvitkine): Switch all platforms to use canvas_skia.cc.
         #                  http://crbug.com/105550
         ['use_canvas_skia==1', {
           'sources!': [
             'gfx/canvas_android.cc',
-            'gfx/canvas_mac.mm',
           ],
         }, {  # use_canvas_skia!=1
           'sources!': [
             'gfx/canvas_skia.cc',
           ],
         }],
         ['use_aura==1', {
           'sources/': [
             ['exclude', 'gfx/gtk_'],
             ['exclude', 'gfx/gtk_util.cc'],
@@ skipping 414 matching lines @@
               'xcode_settings': {
                 'GCC_SYMBOLS_PRIVATE_EXTERN': 'NO',
               },
             }],
           ],
         },
       ],
     }],
   ],
 }