[Mac/GN] Port tweak_info_plist.py and run it on //content targets.

build/mac/tweak_info_plist.py

 #!/usr/bin/env python
 
 # 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.
 
 #
 # Xcode supports build variable substitutions and CPP; sadly, that doesn't work
 # because:
 #
@@ skipping 185 matching lines @@
   tag_keys = []
   for tag_suffix in _TagSuffixes():
     tag_keys.append('KSChannelID' + tag_suffix)
   _RemoveKeys(plist, *tag_keys)
 
 
 def Main(argv):
   parser = optparse.OptionParser('%prog [options]')
   parser.add_option('--plist', dest='plist_path', action='store',
       type='string', default=None, help='The path of the plist to tweak.')
+  parser.add_option('--output', dest='plist_output', action='store',
+      type='string', default=None, help='If specified, the path to output ' + \
+      'the tweaked plist, rather than overwriting the input.')
   parser.add_option('--breakpad', dest='use_breakpad', action='store',
       type='int', default=False, help='Enable Breakpad [1 or 0]')
   parser.add_option('--breakpad_uploads', dest='breakpad_uploads',
       action='store', type='int', default=False,
       help='Enable Breakpad\'s uploading of crash dumps [1 or 0]')
   parser.add_option('--keystone', dest='use_keystone', action='store',
       type='int', default=False, help='Enable Keystone [1 or 0]')
   parser.add_option('--scm', dest='add_scm_info', action='store', type='int',
       default=True, help='Add SCM metadata [1 or 0]')
   parser.add_option('--branding', dest='branding', action='store',
@@ skipping 51 matching lines @@
   # Adds or removes any SCM keys.
   if not _DoSCMKeys(plist, options.add_scm_info):
     return 3
 
   # Now that all keys have been mutated, rewrite the file.
   temp_info_plist = tempfile.NamedTemporaryFile()
   plistlib.writePlist(plist, temp_info_plist.name)
 
   # Info.plist will work perfectly well in any plist format, but traditionally
   # applications use xml1 for this, so convert it to ensure that it's valid.
+  output_path = options.plist_path
+  if options.plist_output is not None:
+    output_path = options.plist_output
   proc = subprocess.Popen(['plutil', '-convert', 'xml1',
-                           '-o', options.plist_path,
+                           '-o', output_path,
                            temp_info_plist.name])
   proc.wait()
   return proc.returncode
 
 
 if __name__ == '__main__':
   sys.exit(Main(sys.argv[1:]))