Print a better error message when someone passes the wrong parameters to

chrome/renderer/resources/renderer_extension_bindings.js

 // Copyright (c) 2009 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.
 
 // This script contains unprivileged javascript APIs related to chrome
 // extensions.  It is loaded by any extension-related context, such as content
 // scripts or toolstrips.
 // See user_script_slave.cc for script that is loaded by content scripts only.
 // TODO(mpcomplete): we also load this in regular web pages, but don't need
 // to.
@@ skipping 150 matching lines @@
     // Opens a message channel to the given target extension, or the current one
     // if unspecified.  Returns a Port for message passing.
     chrome.extension.connect = function(targetId_opt, connectInfo_opt) {
       var name = "";
       var targetId = extensionId;
       var nextArg = 0;
       if (typeof(arguments[nextArg]) == "string")
         targetId = arguments[nextArg++];
       if (typeof(arguments[nextArg]) == "object")
         name = arguments[nextArg++].name || name;
+      if (nextArg != arguments.length)
+        throw new Error("Invalid arguments to connect.");
 
       var portId = OpenChannelToExtension(extensionId, targetId, name);
       if (portId >= 0)
         return chromeHidden.Port.createPort(portId, name);
       throw new Error("Error connecting to extension '" + targetId + "'");
     };
 
     chrome.extension.sendRequest =
         function(targetId_opt, request, responseCallback_opt) {
       var targetId = extensionId;
       var responseCallback = null;
       var lastArg = arguments.length - 1;
       if (typeof(arguments[lastArg]) == "function")
         responseCallback = arguments[lastArg--];
       request = arguments[lastArg--];
-      if (lastArg >= 0)
+      if (lastArg >= 0 && typeof(arguments[lastArg]) == "string")
         targetId = arguments[lastArg--];
+      if (lastArg != -1)
+        throw new Error("Invalid arguments to sendRequest.");
 
       var port = chrome.extension.connect(targetId,
                                           {name: chromeHidden.kRequestChannel});
       port.postMessage(request);
       port.onMessage.addListener(function(response) {
         if (responseCallback)
           responseCallback(response);
         port.disconnect();
       });
     };
@@ skipping 76 matching lines @@
       "extension.onConnectExternal",
       "extension.onRequestExternal",
       "i18n.getAcceptLanguages"
     ];
     for (var i = 0; i < privileged.length; i++) {
       createStub(privileged[i]);
     }
   }
 
 })();