MD Settings: add escape hatch

chrome/browser/resources/settings/settings.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
  * 'cr-settings' is the main MD-Settings element, combining the UI and models.
  *
  * Example:
  *
  *    <cr-settings></cr-settings>
  */
 Polymer({
   is: 'cr-settings',
 
   ready: function() {
     this.$.ui.directionDelegate = new settings.DirectionDelegateImpl;
   },
+
+  properties: {
+    appealClosed_: {
+      type: Boolean,
+      value: function() {
+        return !!sessionStorage.appealClosed_;
+      },
+    },
+  },
+
+  /** @private */
+  onCloseAppealTap_: function(e) {
+    sessionStorage.appealClosed_ = this.appealClosed_ = true;
+  },
 });