Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/extension_custom_bindings.js

Index: chrome/renderer/resources/extensions/extension_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/extension_custom_bindings.js b/chrome/renderer/resources/extensions/extension_custom_bindings.js
index 6444ef3d4a6f3cc8a7897acc3b47907f7265ebac..0e9751e9c94e4a0901b829a8af976e6c011cf35b 100644
--- a/chrome/renderer/resources/extensions/extension_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/extension_custom_bindings.js
@@ -4,10 +4,8 @@
 
 // Custom bindings for the extension API.
 
-(function() {
-
-native function GetChromeHidden();
-native function GetExtensionViews();
+var GetChromeHidden = natives.GetChromeHidden;
+var GetExtensionViews = natives.GetExtensionViews;
 
 // This should match chrome.windows.WINDOW_ID_NONE.
 //
@@ -49,5 +47,3 @@ GetChromeHidden().registerCustomHook('extension', function(bindingsAPI) {
     return GetExtensionViews(windowId, "TAB");
   });
 });
-
-})();