Add whitelist support for grit repack steps.

tools/resources/find_used_resources.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 
 import re
 import sys
 
 usage = """find_used_resources.py
 
 Prints out (to sdout) the sorted list of resource ids that are part of unknown
 pragma warning in the given build log (via stdin).
 
 This script is used to find the resources that are actually compiled in Chrome
 in order to only include the needed strings/images in Chrome PAK files. The
 script parses out the list of used resource ids. These resource ids show up in
 the build output after building Chrome with gyp variable
 enable_resource_whitelist_generation set to 1. This gyp flag causes the compiler
 to print out a UnknownPragma message every time a resource id is used. E.g.:
-foo.cc:22:0: warning: ignoring #pragma IDS_FOO_BAR  [-Wunknown-pragmas]
+foo.cc:22:0: warning: ignoring #pragma whitelisted_resource_12345
+[-Wunknown-pragmas]
 
 """
 
 
 def GetResourceIdsInPragmaWarnings(input):
   """Returns sorted set of resource ids that are inside unknown pragma warnings
      for the given input.
   """
   used_resources = set()
   unknown_pragma_warning_pattern = re.compile('warning: ignoring #pragma '
-      '(?P<resource_id>[A-Z0-9_]*)  \[-Wunknown-pragmas\]')
+      'whitelisted_resource_(?P<resource_id>[0-9]*)  \[-Wunknown-pragmas\]')
   for ln in input:
     match = unknown_pragma_warning_pattern.search(ln)
     if match:
       resource_id = match.group('resource_id')
       used_resources.add(resource_id)
   return sorted(used_resources)
 
 def Main():
   if len(sys.argv) != 1:
     sys.stderr.write(usage)
     sys.exit(1)
   else:
     used_resources = GetResourceIdsInPragmaWarnings(sys.stdin)
     for rid in used_resources:
       sys.stdout.write(rid + '\n')
 
 if __name__ == '__main__':
   Main()