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 "";
    }
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