Lint error fix for pdfjschildbootstrap.js

extensions/firefox/content/pdfjschildbootstrap.js

@@ -1,14 +1,18 @@
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+/* jshint esnext:true */
+/* globals Components, PdfjsContentUtils, PdfJs */
+
+'use strict';
 
 /*
  * pdfjschildbootstrap.js loads into the content process to take care of
  * initializing our built-in version of pdfjs when running remote.
  */
 
-Components.utils.import("resource://pdf.js/PdfJs.jsm");
+Components.utils.import('resource://pdf.js/PdfJs.jsm');
-Components.utils.import("resource://pdf.js/PdfjsContentUtils.jsm");
+Components.utils.import('resource://pdf.js/PdfjsContentUtils.jsm');
 
 // init content utils shim pdfjs will use to access privileged apis.
 PdfjsContentUtils.init();