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

chrome/renderer/resources/extensions/schema_utils.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.
 
 // Routines used to validate and normalize arguments.
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 
 // TODO(benwells): unit test this file.
 // JSONSchemaValidator is not loaded in unit tests.
@@ skipping 18 matching lines @@
             message += "Property '" + err.path + "': ";
           }
           message += err.message;
           message = message.substring(0, message.length - 1);
           message += ", ";
         }
         message = message.substring(0, message.length - 2);
         message += ".";
         throw new Error(message);
       } else if (!parameterSchemas[i].optional) {
-        throw new Error("Parameter " + (i + 1) + " is required.");
+        throw new Error("Parameter " + (i + 1) + " (" +
+            parameterSchemas[i].name + ") is required.");
       }
     }
   };
 } else {
   validate = function() {};
 }
 
 // Generate all possible signatures for a given API function.
 function getSignatures(parameterSchemas) {
   if (parameterSchemas.length === 0)
@@ skipping 102 matching lines @@
         return true;
     }
   }
   return false;
 };
 
 exports.isFunctionSignatureAmbiguous = isFunctionSignatureAmbiguous;
 exports.normalizeArgumentsAndValidate = normalizeArgumentsAndValidate;
 exports.schemaValidator = schemaValidator;
 exports.validate = validate;