Allow updateArgumentsPostValidate to support callbacks and added / removed arguments.

chrome/renderer/resources/extensions/storage_custom_bindings.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // 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() {
   function extendSchema(schema) {
     var extendedSchema = schema.slice();
     extendedSchema.unshift({'type': 'string'});
     return extendedSchema;
   }
 
   function StorageArea(namespace, schema) {
     // Binds an API function for a namespace to its browser-side call, e.g.
     // storage.sync.get('foo') -> (binds to) ->
     // storage.get('sync', 'foo').
     //
     // TODO(kalman): Put as a method on CustomBindingsObject and re-use (or
     // even generate) for other APIs that need to do this. Same for other
     // callers of registerCustomType().
     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)),
             extendSchema(schema));
       };
     }
     var apiFunctions = ['get', 'set', 'remove', 'clear', 'getBytesInUse'];
     apiFunctions.forEach(bindApiFunction.bind(this));
   }
 
   return StorageArea;
 });