Implement a module system for the extension bindings JS.

chrome/renderer/resources/extensions/input.ime_custom_bindings.js

Index: chrome/renderer/resources/extensions/input.ime_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/input.ime_custom_bindings.js b/chrome/renderer/resources/extensions/input.ime_custom_bindings.js
index c6bbbfcac7a5eeecafe7bffcc19e0da242330bca..8f400c780fd3502184137a6a32262de32ff0a27b 100644
--- a/chrome/renderer/resources/extensions/input.ime_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/input.ime_custom_bindings.js
@@ -5,11 +5,9 @@
 // Custom bindings for the input ime API. Only injected into the
 // v8 contexts for extensions which have permission for the API.
 
-(function() {
+var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
-native function GetChromeHidden();
-
-GetChromeHidden().registerCustomHook('input.ime', function() {
+chromeHidden.registerCustomHook('input.ime', function() {
   chrome.input.ime.onKeyEvent.dispatch = function(engineID, keyData) {
     var args = Array.prototype.slice.call(arguments);
     if (this.validate_) {
@@ -36,5 +34,3 @@ GetChromeHidden().registerCustomHook('input.ime', function() {
     }
   };
 });
-
-})();