[MD settings] adding isNewTabPage setting radio buttons

chrome/browser/resources/settings/appearance_page/appearance_page.js

Index: chrome/browser/resources/settings/appearance_page/appearance_page.js
diff --git a/chrome/browser/resources/settings/appearance_page/appearance_page.js b/chrome/browser/resources/settings/appearance_page/appearance_page.js
index 64040af29d925aa8718ecef195779eee434a0425..5bd1f6cec720e95a85f35f6b89837d375bdbe631 100644
--- a/chrome/browser/resources/settings/appearance_page/appearance_page.js
+++ b/chrome/browser/resources/settings/appearance_page/appearance_page.js
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-
-
 /**
  * 'cr-settings-appearance-page' is the settings page containing appearance
  * settings.
@@ -22,6 +20,27 @@
 Polymer({
   is: 'cr-settings-appearance-page',
 
+  properties: {
+    /**
+     * Preferences state.
+     */
+    prefs: {
+      type: Object,
+      notify: true,
+    },
+
+    // prefs.homepage_is_newtabpage.value
+    isNewTabPageString_: {
+      type: String,
+      notify: true,
+      observer: 'isNewTabPageStringChanged_',
+    }
+  },
+
+  observers: [
+    'homepageIsNewTabPageChanged_(prefs.homepage_is_newtabpage.value)',
+  ],
+
   /** @override */
   attached: function() {
     // Query the initial state.
@@ -33,14 +52,15 @@ Polymer({
                         this.setResetThemeEnabled.bind(this));
   },
 
-  properties: {
-    /**
-     * Preferences state.
-     */
-    prefs: {
-      type: Object,
-      notify: true,
-    },
+  /** @private */
+  homepageIsNewTabPageChanged_: function(newValue) {
+    this.isNewTabPageString_ = (newValue == true).toString();
+  },
+
+  /** @private */
+  isNewTabPageStringChanged_: function(newValue) {
+    this.set('prefs.homepage_is_newtabpage.value',
+        this.isNewTabPageString_ == 'true');
   },
 
   setResetThemeEnabled: function(enabled) {