Whitelist environment variables used from Official chrome builds

pylib/gyp/msvs_emulation.py

 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """
 This module helps emulate Visual Studio 2008 behavior on top of other
 build systems, primarily ninja.
 """
 
 import os
@@ skipping 812 matching lines @@
   if '$' in string:
     for old, new in expansions.iteritems():
       assert '$(' not in new, new
       string = string.replace(old, new)
   return string
 
 def _ExtractImportantEnvironment(output_of_set):
   """Extracts environment variables required for the toolchain to run from
   a textual dump output by the cmd.exe 'set' command."""
   envvars_to_save = (
-      'goma_.*', # TODO(scottmg): This is ugly, but needed for goma.
+      'goma_.*',  # TODO(scottmg): This is ugly, but needed for goma.
       'include',
       'lib',
       'libpath',
       'path',
       'pathext',
       'systemroot',
       'temp',
       'tmp',
+
+      # Needed to pass through some chrome flags.
+      # http://crbug.com/333738.
+      'chrom.*',
+      'official_build',
       )
   env = {}
   for line in output_of_set.splitlines():
     for envvar in envvars_to_save:
       if re.match(envvar + '=', line.lower()):
         var, setting = line.split('=', 1)
         if envvar == 'path':
           # Our own rules (for running gyp-win-tool) and other actions in
           # Chromium rely on python being in the path. Add the path to this
           # python here so that if it's not in the path when ninja is run
@@ skipping 98 matching lines @@
 
   # To determine processor word size on Windows, in addition to checking
   # PROCESSOR_ARCHITECTURE (which reflects the word size of the current
   # process), it is also necessary to check PROCESSOR_ARCHITEW6432 (which
   # contains the actual word size of the system when running thru WOW64).
   if ('64' in os.environ.get('PROCESSOR_ARCHITECTURE', '') or
       '64' in os.environ.get('PROCESSOR_ARCHITEW6432', '')):
     default_variables['MSVS_OS_BITS'] = 64
   else:
     default_variables['MSVS_OS_BITS'] = 32