MD Downloads: fix vulcanize issues by excluding higher up in the dependency tree

chrome/browser/resources/md_downloads/vulcanize.py

 #!/usr/bin/env python
 # Copyright 2015 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 16 matching lines @@
 _POLYMER_PATH = os.path.join(
     _SRC_PATH, 'third_party', 'polymer', 'v1_0', 'components-chromium')
 
 _VULCANIZE_ARGS = [
   '--exclude', 'crisper.js',
 
   # These files are already combined and minified.
   '--exclude', 'polymer-extracted.js',
   '--exclude', 'polymer-micro-extracted.js',
   '--exclude', 'polymer-mini-extracted.js',
+  '--exclude', 'web-animations-next-lite.min.js',
+
+  # Because we're excluding polymer-* files, they are run earlier as separate
+  # <script>s. polymer_config.js must run before any polymer-*.js, so it must be
+  # excluded from vulcanization as well to have any effect.
   '--exclude', 'polymer_config.js',
-  '--exclude', 'web-animations-next-lite.min.js',
 
   # These files are dynamically created by C++.
   '--exclude', 'load_time_data.js',
   '--exclude', 'strings.js',
   '--exclude', 'text_defaults.css',
   '--exclude', 'text_defaults_md.css',
 
   '--inline-css',
   '--inline-scripts',
 
@@ skipping 30 matching lines @@
     _run_cmd(['crisper', '--source', tmp.name,
                          '--script-in-head', 'false',
                          '--html', _HTML_OUT_PATH,
                          '--js', _JS_OUT_PATH])
   finally:
     os.remove(tmp.name)
 
 
 if __name__ == '__main__':
   main()