MD Settings: create a shared handler/browser proxy to control extensions

chrome/test/data/webui/settings/test_search_engines_browser_proxy.js

Index: chrome/test/data/webui/settings/test_search_engines_browser_proxy.js
diff --git a/chrome/test/data/webui/settings/test_search_engines_browser_proxy.js b/chrome/test/data/webui/settings/test_search_engines_browser_proxy.js
index ccf09e49f75fc261c64bcfdfa89349a2e24db14d..1055eefc91dc75580114722315b15ea41f1ce44d 100644
--- a/chrome/test/data/webui/settings/test_search_engines_browser_proxy.js
+++ b/chrome/test/data/webui/settings/test_search_engines_browser_proxy.js
@@ -21,8 +21,6 @@ cr.define('settings_search', function() {
       'searchEngineEditStarted',
       'setDefaultSearchEngine',
       'validateSearchEngineInput',
-      'manageExtension',
-      'disableExtension',
     ]);
 
     /** @private {!SearchEnginesInfo} */
@@ -76,16 +74,6 @@ cr.define('settings_search', function() {
       this.methodCalled('validateSearchEngineInput');
       return Promise.resolve(true);
     },
-
-    /** @override */
-    manageExtension: function(extensionId) {
-      this.methodCalled('manageExtension', extensionId);
-    },
-
-    /** @override */
-    disableExtension: function(extensionId) {
-      this.methodCalled('disableExtension', extensionId);
-    },
   };
 
   /**