Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/web_request_custom_bindings.js

Index: chrome/renderer/resources/extensions/web_request_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/web_request_custom_bindings.js b/chrome/renderer/resources/extensions/web_request_custom_bindings.js
index 564251ea4fa70f7a37bb4f8639b8cdce65f31428..392f66c6df77160c906212edf6b8b301301e16bc 100644
--- a/chrome/renderer/resources/extensions/web_request_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/web_request_custom_bindings.js
@@ -4,12 +4,10 @@
 
 // Custom bindings for the webRequest API.
 
-(function() {
+var webRequestNatives = requireNative('web_request');
+var GetUniqueSubEventName = webRequestNatives.GetUniqueSubEventName;
 
-native function GetChromeHidden();
-native function GetUniqueSubEventName(eventName);
-
-var chromeHidden = GetChromeHidden();
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
 // WebRequestEvent object. This is used for special webRequest events with
 // extra parameters. Each invocation of addListener creates a new named
@@ -172,5 +170,3 @@ chromeHidden.registerCustomHook('webRequest', function(api) {
                 {forIOThread: true});
   });
 });
-
-})();