MD Settings: make chrome://[md-]settings/clearBrowserData URL work

chrome/browser/resources/settings/settings_main/settings_main.js

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * @fileoverview
  * 'settings-main' displays the selected settings page.
  */
 Polymer({
   is: 'settings-main',
@@ skipping 41 matching lines @@
       value: true,
     },
 
     /** @private */
     showAboutPage_: {
       type: Boolean,
       value: false,
     },
   },
 
+  created: function() {
+    /** @private {!PromiseResolver} */
+    this.resolver_ = new PromiseResolver;
+    settings.main.rendered = this.resolver_.promise;
+  },
+
   attached: function() {
     document.addEventListener('toggle-advanced-page', function(e) {
       this.showAdvancedPage_ = e.detail;
       this.isAdvancedMenuOpen_ = e.detail;
       if (this.showAdvancedPage_) {
-        scrollWhenReady(
+        doWhenReady(
             function() {
-              return this.$$('settings-advanced-page');
+              var advancedPage = this.$$('settings-advanced-page');
+              return !!advancedPage && advancedPage.scrollHeight > 0;
             }.bind(this),
             function() {
-              return this.$$('#toggleContainer');
+              this.$$('#toggleContainer').scrollIntoView();
             }.bind(this));
       }
     }.bind(this));
+
+    doWhenReady(
+        function() {
+          var basicPage = this.$$('settings-basic-page');
+          return !!basicPage && basicPage.scrollHeight > 0;
+        }.bind(this),
+        function() {
+          this.resolver_.resolve();
+        }.bind(this));
   },
 
   /**
    * @param {boolean} opened Whether the menu is expanded.
    * @return {string} Which icon to use.
    * @private
    * */
   arrowState_: function(opened) {
     return opened ? 'settings:arrow-drop-up' : 'cr:arrow-drop-down';
   },
@@ skipping 16 matching lines @@
         newRoute.page == 'advanced';
 
     this.style.height = isSubpage ? '100%' : '';
   },
 
   /** @private */
   toggleAdvancedPage_: function() {
     this.fire('toggle-advanced-page', !this.isAdvancedMenuOpen_);
   },
 });