Make the externally connectable browser test clobber all of the builtins,

chrome/test/data/extensions/api_test/messaging/externally_connectable/sites/assertions.js

 // Copyright 2013 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.
 
 window.assertions = (function() {
 
+// We are going to kill all of the builtins, so hold onto the ones we need.
+var defineGetter = Object.prototype.__defineGetter__;
+var defineSetter = Object.prototype.__defineSetter__;
+var Error = window.Error;
+var forEach = Array.prototype.forEach;
+var hasOwnProperty = Object.prototype.hasOwnProperty;
+var getOwnPropertyNames = Object.getOwnPropertyNames;
+var stringify = JSON.stringify;
+
+// Kill all of the builtins functions to give us a fairly high confidence that
+// the environment our bindings run in can't interfere with our code.
+// These are taken from the ECMAScript spec.
+var builtinTypes = [
+  Object, Function, Array, String, Boolean, Number, Math, Date, RegExp, JSON,
+];
+
+function clobber(obj, name, description) {

[Jeffrey Yasskin, 2013/06/20 23:33:04]

s/description/qualifiedName/?

[not at google - send to devlin, 2013/06/21 00:01:44]

Done.

+  // Clobbering constructors would break everything.
+  // Clobbering toString is annoying.
+  // Clobbering __proto__ breaks in ways that grep can't find.
+  // Clobbering Function.call would make it impossible to implement these tests.
+  // Clobbering Object.valueOf breaks v8.
+  if (name == 'constructor' ||
+      name == 'toString' ||
+      name == '__proto__' ||
+      description == 'Function.call' ||
+      description == 'Object.valueOf') {
+    return;
+  }
+  if (typeof(obj[name]) == 'function') {
+    obj[name] = function() {
+      throw new Error('Clobbered ' + description + ' function');
+    };
+  } else {
+    defineGetter.call(obj, name, function() {
+      throw new Error('Clobbered ' + description + ' getter');
+    });
+  }
+}
+
+forEach.call(builtinTypes, function(builtin) {
+  var prototype = builtin.prototype;
+  if (prototype) {
+    forEach.call(getOwnPropertyNames(prototype), function(name) {
+      clobber(prototype, name, prototype.constructor.name + '.' + name);
+    });
+  }
+  forEach.call(getOwnPropertyNames(builtin), function(name) {
+    clobber(builtin, name, name);

[Jeffrey Yasskin, 2013/06/20 23:33:04]

'name' doesn't seem right for the qualified name here. Can you use
<typename>.name instead? Clearly you're not using this now, but it may save some
confusion in the future.

[not at google - send to devlin, 2013/06/21 00:01:44]

Done

+  });
+  if (builtin.name)
+    clobber(window, builtin.name, 'window.' + builtin.name);
+});
+
 // Codes for test results. Must match ExternallyConnectableMessagingTest::Result
 // in c/b/extensions/extension_messages_apitest.cc.
 var results = {
   OK: 0,
   NAMESPACE_NOT_DEFINED: 1,
   FUNCTION_NOT_DEFINED: 2,
   COULD_NOT_ESTABLISH_CONNECTION_ERROR: 3,
   OTHER_ERROR: 4,
   INCORRECT_RESPONSE_SENDER: 5,
   INCORRECT_RESPONSE_MESSAGE: 6
@@ skipping 13 matching lines @@
     reply(results.OTHER_ERROR);
   return false;
 }
 
 function checkResponse(response, reply) {
   // The response will be an echo of both the original message *and* the
   // MessageSender (with the tab field stripped down).
   //
   // First check the sender was correct.
   var incorrectSender = false;
-  if (!response.sender.hasOwnProperty('tab')) {
+  if (!hasOwnProperty.call(response.sender, 'tab')) {
     console.warn('Expected a tab, got none');
     incorrectSender = true;
   }
   if (response.sender.tab.url != document.location.href) {
     console.warn('Expected tab url ' + document.location.href + ' got ' +
                  response.sender.tab.url);
     incorrectSender = true;
   }
-  if (response.sender.hasOwnProperty('id')) {
+  if (hasOwnProperty.call(response.sender, 'id')) {
     console.warn('Expected no id, got "' + response.sender.id + '"');
     incorrectSender = true;
   }
   if (response.sender.url != document.location.href) {
     console.warn('Expected url ' + document.location.href + ' got ' +
                  response.sender.url);
     incorrectSender = true;
   }
   if (incorrectSender) {
     reply(results.INCORRECT_RESPONSE_SENDER);
     return false;
   }
 
   // Check the correct content was echoed.
-  var expectedJson = JSON.stringify(message);
-  var actualJson = JSON.stringify(response.message);
+  var expectedJson = stringify(message);
+  var actualJson = stringify(response.message);
   if (actualJson == expectedJson)
     return true;
   console.warn('Expected message ' + expectedJson + ' got ' + actualJson);
   reply(results.INCORRECT_RESPONSE_MESSAGE);
   return false;
 }
 
-var sendToBrowser = domAutomationController.send.bind(domAutomationController);
+function sendToBrowser(msg) {
+  domAutomationController.send(msg);
+}
 
 return {
   canConnectAndSendMessages: function(extensionId) {
     if (!chrome.runtime) {
       sendToBrowser(results.NAMESPACE_NOT_DEFINED);
       return;
     }
 
     if (!chrome.runtime.sendMessage || !chrome.runtime.connect) {
       sendToBrowser(results.FUNCTION_NOT_DEFINED);
@@ skipping 29 matching lines @@
       if (result != results.OK)
         sendToBrowser(result);
       else
         canConnectAndSendMessages(sendToBrowser);
     });
   },
 
   areAnyRuntimePropertiesDefined: function(names) {
     var result = false;
     if (chrome.runtime) {
-      names.forEach(function(name) {
+      forEach.call(names, function(name) {
         if (chrome.runtime[name]) {
           console.log('runtime.' + name + ' is defined');
           result = true;
         }
       });
     }
     sendToBrowser(result);
   }
 };
 
 }());  // window.assertions