[Presubmit] Make CSS checker ignore '@' inside of strings.

chrome/browser/web_dev_style/css_checker.py

 # 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.
 
 """Presubmit script for Chromium WebUI resources.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into gcl/git cl, and see
 http://www.chromium.org/developers/web-development-style-guide for the rules
 we're checking against here.
@@ skipping 15 matching lines @@
       return (len(s) == 6 and s[0] == s[1] and s[2] == s[3] and s[4] == s[5])
 
     def _is_gray(s):
       return s[0] == s[1] == s[2] if len(s) == 3 else s[0:2] == s[2:4] == s[4:6]
 
     def _remove_all(s):
       return _remove_grit(_remove_ats(_remove_comments(s)))
 
     def _remove_ats(s):
       at_reg = re.compile(r"""
-          @\w+.*?{    # @at-keyword selector junk {
-          (.*{.*?})+  # inner { curly } blocks, rules, and selector junk
-          .*?}        # stuff up to the first end curly }""",
+          @\w+[^'"]*?{  # @at-keyword selector junk {
+          (.*{.*?})+    # inner { curly } blocks, rules, and selector junk
+          .*?}          # stuff up to the first end curly }""",
           re.DOTALL | re.VERBOSE)
       return at_reg.sub('\\1', s)
 
     def _remove_comments(s):
       return re.sub(re.compile(r'/\*.*?\*/', re.DOTALL), '', s)
 
     def _remove_grit(s):
       grit_reg = re.compile(r"""
           <if[^>]+>.*?<\s*/\s*if[^>]*>|  # <if> contents </if>
           <include[^>]+>                 # <include>""",
@@ skipping 314 matching lines @@
             '%s:\n%s' % (f[0], '\n\n'.join(file_errors))))
 
     if results:
       # Add your name if you're here often mucking around in the code.
       authors = ['dbeam@chromium.org']
       results.append(self.output_api.PresubmitNotifyResult(
           'Was the CSS checker useful? Send feedback or hate mail to %s.' %
           ', '.join(authors)))
 
     return results