Initial work to remove the notion of all extension message payloads as strings.

chrome/renderer/resources/extensions/json_schema.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.
 
 // -----------------------------------------------------------------------------
 // NOTE: If you change this file you need to touch renderer_resources.grd to
 // have your change take effect.
 // -----------------------------------------------------------------------------
 
 //==============================================================================
@@ skipping 106 matching lines @@
  * the input values.
  */
 chromeHidden.JSONSchemaValidator.getType = function(value) {
   var s = typeof value;
 
   if (s == "object") {
     if (value === null) {
       return "null";
     } else if (Object.prototype.toString.call(value) == "[object Array]") {
       return "array";
+    } else if (value.constructor == ArrayBuffer) {
+      return "binary";
     }
   } else if (s == "number") {
     if (value % 1 == 0) {
       return "integer";
     }
   }
 
   return s;
 };
 
@@ skipping 361 matching lines @@
     message: chromeHidden.JSONSchemaValidator.formatError(key, replacements)
   });
 };
 
 /**
  * Resets errors to an empty list so you can call 'validate' again.
  */
 chromeHidden.JSONSchemaValidator.prototype.resetErrors = function() {
   this.errors = [];
 };