Use window.localStorage in all cases

src/app/storage-handler.js

-/* global chrome, confirm, localStorage */
+/* global chrome, confirm */
 
 var utils = require('./utils');
 
@@ -17,11 +17,11 @@ function StorageHandler (updateFiles) {
         console.log('comparing to cloud', key, resp);
         if (typeof resp[key] !== 'undefined' && obj[key] !== resp[key] && confirm('Overwrite "' + utils.fileNameFromKey(key) + '"? Click Ok to overwrite local file with file from cloud. Cancel will push your local file to the cloud.')) {
           console.log('Overwriting', key);
-          localStorage.setItem(key, resp[key]);
+          window.localStorage.setItem(key, resp[key]);
           updateFiles();
         } else {
           console.log('add to obj', obj, key);
-          obj[key] = localStorage[key];
+          obj[key] = window.localStorage[key];
         }
         done++;
         if (done >= count) {