Add Skia on Chrome for Mac gyp rules

printing/printing.gyp

 # Copyright (c) 2011 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 89 matching lines @@
             'sources/': [['exclude', '_posix\\.cc$']]
         }],
         ['toolkit_uses_gtk == 1', {
           'dependencies': [
             # For FT_Init_FreeType and friends.
             '../build/linux/system.gyp:freetype2',
             '../build/linux/system.gyp:gtk',
             '../build/linux/system.gyp:gtkprint',
           ],
         }],
-        ['OS=="mac"',
-          {'sources/': [
+        ['OS=="mac" and use_skia==0', {
+          'sources/': [
             ['exclude', 'pdf_metafile_skia\\.(cc|h)$'],
             ['exclude', 'metafile_skia_wrapper\\.(cc|h)$'],
-        ]}],
+          ],
+        }],
         ['OS=="win"', {
           'defines': [
             # PRINT_BACKEND_AVAILABLE disables the default dummy implementation
             # of the print backend and enables a custom implementation instead.
             'PRINT_BACKEND_AVAILABLE',
           ],
           'sources': [
             'backend/win_helper.cc',
             'backend/win_helper.h',
             'backend/print_backend_win.cc',
@@ skipping 96 matching lines @@
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: