Rework build/mac/tweak_info_plist.py to not rely on environment variables.

chrome/chrome_exe.gypi

 # 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.
 
 {
   'targets': [
     {
       # GN version: //chrome
       'target_name': 'chrome',
       'type': 'none',
@@ skipping 323 matching lines @@
               # is needed.  This is also done in the helper_app and chrome_dll
               # targets.  Use --breakpad=0 to not include any Breakpad
               # information; that all goes into the framework's Info.plist.
               # Keystone information is included if Keystone is enabled.  The
               # application reads Keystone keys from this plist and not the
               # framework's, and the ticket will reference this Info.plist to
               # determine the tag of the installed product.  Use --scm=1 to
               # include SCM information.
               'postbuild_name': 'Tweak Info.plist',
               'action': ['<(tweak_info_plist_path)',
+                         '--plist=${TARGET_BUILD_DIR}/${INFOPLIST_PATH}',
                          '--breakpad=0',
                          '--keystone=<(mac_keystone)',
                          '--scm=1',
                          '--bundle_id=<(mac_bundle_id)'],
             },
             {
               'postbuild_name': 'Clean up old versions',
               'action': [
                 'tools/build/mac/clean_up_old_versions',
                 '<(version_full)'
@@ skipping 246 matching lines @@
               'dependencies': [
                 'chrome_nacl_win64',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }