[MD settings] adding homepage url input

chrome/browser/resources/settings/appearance_page/appearance_page.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.
 
 /**
  * 'cr-settings-appearance-page' is the settings page containing appearance
  * settings.
  *
  * Example:
  *
@@ skipping 11 matching lines @@
 
   properties: {
     /**
      * Preferences state.
      */
     prefs: {
       type: Object,
       notify: true,
     },
 
+    // prefs.homepage.value
+    homepage_: {
+      type: String,
+      notify: true,
+    },
+
     i18n_: {
       type: Object,
       value: function() {
         return {
+          changeHomePage: loadTimeData.getString('changeHomePage'),
           homePageNtp: loadTimeData.getString('homePageNtp'),
           openThisPage: loadTimeData.getString('openThisPage'),
+          onStartupEnterUrl: loadTimeData.getString('onStartupEnterUrl'),
         };
       },
     },
 
     // prefs.homepage_is_newtabpage.value
     isNewTabPageString_: {
       type: String,
       notify: true,
       observer: 'isNewTabPageStringChanged_',
-    }
+    },
   },
 
   observers: [
     'homepageIsNewTabPageChanged_(prefs.homepage_is_newtabpage.value)',
+    'homepageChanged_(prefs.homepage.value)',
   ],
 
   /** @override */
   attached: function() {
     // Query the initial state.
     cr.sendWithCallback('getResetThemeEnabled', undefined,
                         this.setResetThemeEnabled.bind(this));
 
     // Set up the change event listener.
     cr.addWebUIListener('reset-theme-enabled-changed',
                         this.setResetThemeEnabled.bind(this));
   },
 
   /** @private */
+  onSetHomepageTap_: function() {
+    this.set('prefs.homepage.value', this.homepage_);
+  },
+
+  /** @private */
+  homepageChanged_: function(newValue) {
+    this.homepage_ = newValue;
+  },
+
+  /** @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) {
     this.$.resetTheme.disabled = !enabled;
   },
 
   /** @private */
   openThemesGallery_: function() {
     window.open(loadTimeData.getString('themesGalleryUrl'));
   },
 
   /** @private */
   resetTheme_: function() {
     chrome.send('resetTheme');
   },
 });