extensions: Remove dependency on chrome's common target.

chrome/common_constants.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': [
     '../build/util/version.gypi',
   ],
 
   'target_defaults': {
     'sources': [
-      # TODO(yoz): Create an extension_constants target for these.
-      '../extensions/common/constants.cc',
-      '../extensions/common/constants.h',
       'common/chrome_constants.cc',
       'common/chrome_constants.h',
       'common/chrome_icon_resources_win.cc',
       'common/chrome_icon_resources_win.h',
       'common/chrome_paths.cc',
       'common/chrome_paths.h',
       'common/chrome_paths_android.cc',
       'common/chrome_paths_internal.h',
       'common/chrome_paths_linux.cc',
       'common/chrome_paths_mac.mm',
@@ skipping 81 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }