MD Settings: Convert all usages of .bind(this) to use ES6 arrow function.

chrome/browser/resources/settings/device_page/storage.js

Index: chrome/browser/resources/settings/device_page/storage.js
diff --git a/chrome/browser/resources/settings/device_page/storage.js b/chrome/browser/resources/settings/device_page/storage.js
index 0e592fc1b49b9e0d739b2890034e4e3b3eac1651..99a959df779575dbb85e618a758fb6b22d39b2c2 100644
--- a/chrome/browser/resources/settings/device_page/storage.js
+++ b/chrome/browser/resources/settings/device_page/storage.js
@@ -246,13 +246,13 @@ Polymer({
   startPeriodicUpdate_: function() {
     // We update the storage usage every 5 seconds.
     if (this.updateTimerId_ == -1) {
-      this.updateTimerId_ = window.setInterval(function() {
+      this.updateTimerId_ = window.setInterval(() => {
         if (settings.getCurrentRoute() != settings.routes.STORAGE) {
           this.stopPeriodicUpdate_();
           return;
         }
         chrome.send('updateStorageInfo');
-      }.bind(this), 5000);
+      }, 5000);
     }
   },