Make common depend on app_mode_app_support.

chrome/chrome.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,
 
     # Define the common dependencies that contain all the actual
     # Chromium functionality.  This list gets pulled in below by
     # the link of the actual chrome (or chromium) executable on
@@ skipping 259 matching lines @@
                   #                                    Helper.app/Contents/MacOS
                   '@loader_path/../../../../../../..',
                 ],
               },
             }],
           ],
         },  # target helper_app
         {
           # A library containing the actual code for the app mode app, shared
           # by unit tests.
+          # GN: //chrome/common:app_mode_app_support
           'target_name': 'app_mode_app_support',
           'type': 'static_library',
           'variables': { 'enable_wexit_time_destructors': 1, },
           'product_name': 'app_mode_app_support',
           'dependencies': [
             '../base/base.gyp:base',
             'common_constants.gyp:common_constants',
           ],
           'sources': [
             'common/mac/app_mode_chrome_locator.h',
@@ skipping 524 matching lines @@
                   '<(DEPTH)/third_party/kasko'
                 ],
               },
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }