Add Now setting and migration logic.

chrome/browser/resources/options/browser_options.js

Index: chrome/browser/resources/options/browser_options.js
diff --git a/chrome/browser/resources/options/browser_options.js b/chrome/browser/resources/options/browser_options.js
index d9470ff7ed4984d105cf420a9d0d7b4514ce23ab..80d433c7db249dd8f7739657ffc8139d64ddd753 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -246,6 +246,8 @@ cr.define('options', function() {
           $('hotword-always-on-search-checkbox');
       chrome.send('requestHotwordAvailable');
 
+      chrome.send('requestGoogleNowAvailable');
+
       if ($('set-wallpaper')) {
         $('set-wallpaper').onclick = function(event) {
           chrome.send('openWallpaperManager');
@@ -1254,6 +1256,15 @@ cr.define('options', function() {
     },
 
     /**
+     * Controls the visibility of the Now settings.
+     * @param {boolean} visible Whether to show Now settings.
+     * @private
+     */
+    setNowSectionVisible_: function(visible) {
+      $('google-now-launcher').hidden = !visible;
+    },
+
+    /**
      * Activates the Audio History section of the Settings page.
      * @param {boolean} visible Whether the audio history section is visible.
      * @param {string} labelText Text describing current audio history state.
@@ -2173,6 +2184,7 @@ cr.define('options', function() {
     'setHotwordRetrainLinkVisible',
     'setNativeThemeButtonEnabled',
     'setNetworkPredictionValue',
+    'setNowSectionVisible',
     'setHighContrastCheckboxState',
     'setAllHotwordSectionsVisible',
     'setMetricsReportingCheckboxState',