MD Extensions: Convert classes to use ES6 class syntax.

chrome/browser/resources/md_extensions/navigation_helper.js

Index: chrome/browser/resources/md_extensions/navigation_helper.js
diff --git a/chrome/browser/resources/md_extensions/navigation_helper.js b/chrome/browser/resources/md_extensions/navigation_helper.js
index 43e23820a89a1f45ef55aa445b31e9c14015b72f..d15ca599647902099a8a86091b3119c989129139 100644
--- a/chrome/browser/resources/md_extensions/navigation_helper.js
+++ b/chrome/browser/resources/md_extensions/navigation_helper.js
@@ -31,26 +31,28 @@ cr.define('extensions', function() {
    * A helper object to manage in-page navigations. Since the extensions page
    * needs to support different urls for different subpages (like the details
    * page), we use this object to manage the history and url conversions.
-   * @param {!function(!PageState):void} onHistoryChange A function to call when
-   *     the page has changed as a result of the user going back or forward in
-   *     history; called with the new active page.
-   * @constructor */
-  function NavigationHelper(onHistoryChange) {
-    this.onHistoryChange_ = onHistoryChange;
-    window.addEventListener('popstate', this.onPopState_.bind(this));
-  }
+   */
+  class NavigationHelper {
+    /**
+     * @param {!function(!PageState):void} onHistoryChange A function to call
+     *     when the page has changed as a result of the user going back or
+     *     forward in history; called with the new active page.
+     */
+    constructor(onHistoryChange) {
+      this.onHistoryChange_ = onHistoryChange;
+      window.addEventListener('popstate', this.onPopState_.bind(this));
+    }
 
-  NavigationHelper.prototype = {
     /** @private */
-    onPopState_: function() {
+    onPopState_() {
       this.onHistoryChange_(this.getCurrentPage());
-    },
+    }
 
     /**
-     * Returns the page that should be displayed for the current URL.
-     * @return {!PageState}
+     * @return {!PageState} The page that should be displayed for the current
+     *     URL.
      */
-    getCurrentPage: function() {
+    getCurrentPage() {
       var search = new URLSearchParams(location.search);
       var id = search.get('id');
       if (id)
@@ -66,13 +68,13 @@ cr.define('extensions', function() {
         return {page: Page.SHORTCUTS};
 
       return {page: Page.LIST};
-    },
+    }
 
     /**
      * Called when a page changes, and pushes state to history to reflect it.
      * @param {!PageState} entry
      */
-    updateHistory: function(entry) {
+    updateHistory(entry) {
       var path;
       switch (entry.page) {
         case Page.LIST:
@@ -106,8 +108,8 @@ cr.define('extensions', function() {
         history.replaceState(state, '', path);
       else
         history.pushState(state, '', path);
-    },
-  };
+    }
+  }
 
   return {NavigationHelper: NavigationHelper};
 });