code: function _getStringAtPos(hostEditor, pos) {
          var token = hostEditor._codeMirror.getTokenAt(pos, true);
  
          // If the pos is at the beginning of a name, token will be the
          // preceding whitespace or dot. In that case, try the next pos.
          if (!/\S/.test(token.string) || token.string === ".") {
              token = hostEditor._codeMirror.getTokenAt({line: pos.line, ch: pos.ch + 1}, true);
          }
  
          if (token.type === "string") {
              var string = token.string;
  
              // Strip quotes
              var ch = string[0];
              if (ch === "\"" || ch === "'") {
                  string = string.substr(1);
              }
              ch = string[string.length - 1];
              if (ch === "\"" || ch === "'") {
                  string = string.substr(0, string.length - 1);
              }
  
              return string;
          } else {
  
              // Check for url(...);
              var line = hostEditor._codeMirror.getLine(pos.line);
              var match = /url\s*\(([^)]*)\)/.exec(line);
  
              if (match && match[1]) {
                  // URLs are relative to the doc
                  var docPath = hostEditor.document.file.fullPath;
  
                  docPath = docPath.substr(0, docPath.lastIndexOf("/"));
  
                  return docPath + "/" + match[1];
              }
          }
  
          return "";
      }
docs: Return the token string that is at the specified position.
  
  @param hostEditor {!Editor} editor
  @param {!{line:Number, ch:Number}} pos
  @return {String} token string at the specified position