Integrate About page into Settings for Chrome OS settings in a window.

ui/webui/resources/js/cr/ui/page_manager/page.js

Index: ui/webui/resources/js/cr/ui/page_manager/page.js
diff --git a/ui/webui/resources/js/cr/ui/page_manager/page.js b/ui/webui/resources/js/cr/ui/page_manager/page.js
index b9d92593c7ec8638dc32cf45613992e5185d296d..ae74047794502c54b832bd6dc18bb779bfdea2e5 100644
--- a/ui/webui/resources/js/cr/ui/page_manager/page.js
+++ b/ui/webui/resources/js/cr/ui/page_manager/page.js
@@ -66,6 +66,22 @@ cr.define('cr.ui.pageManager', function() {
     initializePage: function() {},
 
     /**
+     * Called when a page becomes visible.
+     */
+    didShowPage: function() {},
+
+    /**
+     * Called when a page will be hidden, i.e., when a different root page is
+     * about to be shown.
+     */
+    willHidePage: function() {},
+
+    /**
+     * Called when an overlay is closed.
+     */
+    didClosePage: function() {},
+
+    /**
      * Sets focus on the first focusable element. Override for a custom focus
      * strategy.
      */