Add new instant extended specific pref.

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 7ac6f17a521471c5f2ae3434dac3c0ee82a70698..26e44090b33eac97f483bd5306072b384854ac5a 100644
--- a/chrome/browser/resources/options/browser_options.js
+++ b/chrome/browser/resources/options/browser_options.js
@@ -158,6 +158,19 @@ cr.define('options', function() {
       };
       $('default-search-engine').addEventListener('change',
           this.setDefaultSearchEngine_);
+      if (loadTimeData.getValue('instant_extended')) {
+        // The control must be duplicated because we can't change the pref
+        // attribute here, it would be too late, since the value is initialized
+        // earlier using the original pref name, so we swap the controls.
+        $('instant-enabled-control').hidden = true;
+        $('instant-extended-enabled-control').hidden = false;
+        // For the other elements, we can simply modify them here as follows.
+        $('instant-enabled-indicator').removeAttribute('dialog-pref');
+        $('instant-enabled-control').setAttribute('pref',
+                                                  'instant_extended.enabled');
+        $('instant-enabled-control-label').setAttribute(
+            'for', 'instant-extended-enabled-control');
+      }
 
       // Users section.
       if (loadTimeData.valueExists('profilesInfo')) {