[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..f1f5879f2177bd4d53d77801126691efe2915ec3 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 ? 't' : 'f';

[Dan Beam, 2015/09/16 00:23:19]

if you change to 'true'/'false' (which is the same as true.toString() and
false.toString()), do you need this method?

[dschuyler, 2015/09/16 01:37:30]

It kinda works and kinda doesn't.  The part that doesn't work is the initial
value.  The initial value won't be set on load, but after the user clicks either
of the radio buttons, then they work fine.  This may be worth tinkering with
further, unless Steven is really going to replace it all with something that 
handles string/bool/int in a radio group (then I'd feel silly putting a lot of
time into making
something that only handles bools).

+  },
+
+  /** @private */
+  isNewTabPageStringChanged_: function(newValue) {
+    this.set('prefs.homepage_is_newtabpage.value',
+        this.isNewTabPageString == 't' ? true : false);
   },
 
   setResetThemeEnabled: function(enabled) {