[Extensions] Don't allow built-in extensions code to be overridden

extensions/renderer/api_test_base.cc

 // Copyright 2014 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.
 
 #include "extensions/renderer/api_test_base.h"
 
 #include <vector>
 
 #include "base/run_loop.h"
 #include "extensions/common/extension_urls.h"
@@ skipping 122 matching lines @@
           env()->context()->GetExtensionID(),
           env()->context()->GetContextTypeDescription(),
           false,
           false,
           2,
           false)));
   env()->RegisterTestFile("test_environment_specific_bindings",
                           "unit_test_environment_specific_bindings.js");
 
   env()->OverrideNativeHandler("activityLogger",
-                               "exports.LogAPICall = function() {};");
+                               "exports.$set('LogAPICall', function() {});");
   env()->OverrideNativeHandler(
       "apiDefinitions",
-      "exports.GetExtensionAPIDefinitionsForTest = function() { return [] };");
+      "exports.$set('GetExtensionAPIDefinitionsForTest',"
+                    "function() { return [] });");
   env()->OverrideNativeHandler(
       "event_natives",
-      "exports.AttachEvent = function() {};"
-      "exports.DetachEvent = function() {};"
-      "exports.AttachFilteredEvent = function() {};"
-      "exports.AttachFilteredEvent = function() {};"
-      "exports.MatchAgainstEventFilter = function() { return [] };");
+      "exports.$set('AttachEvent', function() {});"
+      "exports.$set('DetachEvent', function() {});"
+      "exports.$set('AttachFilteredEvent', function() {});"
+      "exports.$set('AttachFilteredEvent', function() {});"
+      "exports.$set('MatchAgainstEventFilter', function() { return [] });");
 
   gin::ModuleRegistry::From(env()->context()->v8_context())
       ->AddBuiltinModule(env()->isolate(),
                          mojo::js::Core::kModuleName,
                          mojo::js::Core::GetModule(env()->isolate()));
   gin::ModuleRegistry::From(env()->context()->v8_context())
       ->AddBuiltinModule(env()->isolate(),
                          mojo::js::Support::kModuleName,
                          mojo::js::Support::GetModule(env()->isolate()));
   gin::Handle<TestServiceProvider> service_provider =
@@ skipping 67 matching lines @@
   test_env_.reset(new ApiTestEnvironment(env()));
 }
 
 void ApiTestBase::RunTest(const std::string& file_name,
                           const std::string& test_name) {
   ExpectNoAssertionsMade();
   test_env_->RunTest(file_name, test_name);
 }
 
 }  // namespace extensions