add: return ""; 
context: function getContentTypeFromHeaders(cacheEntryDescriptor){  var headers, match;  if (cacheEntryDescriptor)  {      headers = cacheEntryDescriptor.getMetaDataElement("response-head");    match = /^Content-Type:\s*(.*?)\s*(?:\;|$)/mi.exec(headers);    return match[1];  }}
meta: 5459	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5459/990ac59712fd27095d2c0e9d94bd897f3c9c8681/pageInfo.js/clean/xpfe/browser/resources/content/pageInfo.js