[MD settings] idle load basic and advanced pages

chrome/test/data/webui/settings/settings_page_browsertest.js

Index: chrome/test/data/webui/settings/settings_page_browsertest.js
diff --git a/chrome/test/data/webui/settings/settings_page_browsertest.js b/chrome/test/data/webui/settings/settings_page_browsertest.js
index a1c5ef5426d0656bc5cccf3cf418020abd98521f..52b1fb3f5c9259b22f85c19866979962a3cad4f3 100644
--- a/chrome/test/data/webui/settings/settings_page_browsertest.js
+++ b/chrome/test/data/webui/settings/settings_page_browsertest.js
@@ -62,6 +62,11 @@ SettingsPageBrowserTest.prototype = {
     var pageType = 'settings-' + type + '-page';
     var page = settingsMain.$$(pageType);
     assertTrue(!!page);
+    var idleRender = page.$$('template[is=settings-idle-render]');
+    if (idleRender) {
+      idleRender.get();
+      Polymer.dom.flush();
+    }
     return page;
   },