MD History: Run polymer-css-build over vulcanized output

chrome/browser/resources/vulcanize.py

 #!/usr/bin/env python
 # Copyright 2016 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 os
 import subprocess
 import sys
 import tempfile
 
@@ skipping 74 matching lines @@
                          '--script-in-head', 'false',
                          '--html', html_out_path,
                          '--js', js_out_path])
 
     # TODO(tsergeant): Remove when JS resources are minified by default:
     # crbug.com/619091.
     _run_cmd(['uglifyjs', js_out_path,
                          '--beautify', 'indent-level=2,quote_style=3',
                          '--comments', '/Copyright|license|LICENSE|\<\/?if/',
                          '--output', js_out_path])
+    _run_cmd(['polymer-css-build', html_out_path])
   finally:
     os.remove(tmp.name)
 
 
 def main():
   _vulcanize(directory='md_downloads', host='downloads',
              html_in_file='downloads.html')
 
   # Already loaded by history.html:
   history_extra_args = ['--exclude', 'chrome://resources/html/util.html',
                         '--exclude', 'chrome://history/constants.html']
   _vulcanize(directory='md_history', host='history', html_in_file='app.html',
              html_out_file='app.vulcanized.html', js_out_file='app.crisper.js',
              extra_args=history_extra_args)
 
 
 if __name__ == '__main__':
   main()