Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/devtools_custom_bindings.js

Index: chrome/renderer/resources/extensions/devtools_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/devtools_custom_bindings.js b/chrome/renderer/resources/extensions/devtools_custom_bindings.js
index d1ad34c248a9aa8f2eae577d24aa2e1743c4ad2e..9d1d8eb80eee5e4de7e249c833907dbbd2f82c33 100644
--- a/chrome/renderer/resources/extensions/devtools_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/devtools_custom_bindings.js
@@ -4,11 +4,9 @@
 
 // Custom bindings for the devtools API.
 
-(function() {
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
-native function GetChromeHidden();
-
-GetChromeHidden().registerCustomHook('devtools', function(bindingsAPI) {
+chromeHidden.registerCustomHook('devtools', function(bindingsAPI) {
   var apiFunctions = bindingsAPI.apiFunctions;
 
   apiFunctions.setHandleRequest('getTabEvents', function(tabId) {
@@ -23,5 +21,3 @@ GetChromeHidden().registerCustomHook('devtools', function(bindingsAPI) {
     return tabIdProxy;
   });
 });
-
-})();