[Extensions Bindings] Add a messaging test

chrome/renderer/resources/extensions/tabs_custom_bindings.js

Index: chrome/renderer/resources/extensions/tabs_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/tabs_custom_bindings.js b/chrome/renderer/resources/extensions/tabs_custom_bindings.js
index bd1f75a184b9c7e2e87568fe53cb1663704295c8..8566625bc6d1f53e4d41ddb7936c38a3a211a3ff 100644
--- a/chrome/renderer/resources/extensions/tabs_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/tabs_custom_bindings.js
@@ -4,7 +4,7 @@
 
 // Custom binding for the tabs API.
 
-var binding = require('binding').Binding.create('tabs');
+var binding = apiBridge || require('binding').Binding.create('tabs');
 
 var messaging = require('messaging');
 var OpenChannelToTab = requireNative('messaging_natives').OpenChannelToTab;
@@ -52,4 +52,5 @@ binding.registerCustomHook(function(bindingsAPI, extensionId) {
   });
 });
 
-exports.$set('binding', binding.generate());
+if (!apiBridge)
+  exports.$set('binding', binding.generate());