Allow updateArgumentsPostValidate to support callbacks and added / removed arguments.

chrome/renderer/resources/extensions/storage_custom_bindings.js

Index: chrome/renderer/resources/extensions/storage_custom_bindings.js
diff --git a/chrome/renderer/resources/extensions/storage_custom_bindings.js b/chrome/renderer/resources/extensions/storage_custom_bindings.js
index 7d8eaa1ef6307c0f382d329d81941d0bef25be00..ed8368415de94513a580dd946b626632d23bbf25 100644
--- a/chrome/renderer/resources/extensions/storage_custom_bindings.js
+++ b/chrome/renderer/resources/extensions/storage_custom_bindings.js
@@ -5,6 +5,8 @@
 // Custom bindings for the storage API.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
+var normalizeArgumentsAndValidate =
+    require('validateUtils').normalizeArgumentsAndValidate
 var sendRequest = require('sendRequest').sendRequest;
 
 chromeHidden.registerCustomType('storage.StorageArea', function() {
@@ -25,7 +27,8 @@ chromeHidden.registerCustomType('storage.StorageArea', function() {
     function bindApiFunction(functionName) {
       this[functionName] = function() {
         var schema = this.parameters[functionName];
-        chromeHidden.validate(arguments, schema);
+        var funDef = this.funDefs[functionName];
+        arguments = normalizeArgumentsAndValidate(arguments, funDef);

[not at google - send to devlin, 2012/06/07 00:17:11]

I don't think that overwriting "arguments" is a polite thing to do. Can you call
it "args".

I'm actually a bit surprised that passing an arguments object into
normalizeArgumentsAndValidate works. It expects an array, so you'll need to
Array.prototype.slice.call it when passing through to
normalizeArgumentsAndValidate. And... add a comment to
normalizeArgumentsAndValidate to say that |args| should be an array :p

[benwells, 2012/06/07 01:45:40]

Done.

         return sendRequest(
             'storage.' + functionName,
             [namespace].concat(Array.prototype.slice.call(arguments)),