unbreak assetpath generation

Author: dfreedm

lib/constants.js

@@ -9,6 +9,7 @@ var URL_ATTR = ['href', 'src', 'action', 'style'];
 
 module.exports = {
   EOL: require('os').EOL,
+  ELEMENTS: 'polymer-element',
   ABS_URL: /(^data:)|(^http[s]?:)|(^\/)/,
   IMPORTS: 'link[rel="import"][href]',
   URL: /url\([^)]*\)/g,