Standardize usage of virtual/override/final in extensions/

extensions/renderer/module_system_unittest.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 "base/memory/scoped_ptr.h"
 #include "extensions/renderer/module_system.h"
 #include "extensions/renderer/module_system_test.h"
 #include "gin/modules/module_registry.h"
 
 namespace extensions {
@@ skipping 18 matching lines @@
   }
 
  private:
   int counter_;
 };
 
 class TestExceptionHandler : public ModuleSystem::ExceptionHandler {
  public:
   TestExceptionHandler() : handled_exception_(false) {}
 
-  virtual void HandleUncaughtException(const v8::TryCatch& try_catch) override {
+  void HandleUncaughtException(const v8::TryCatch& try_catch) override {
     handled_exception_ = true;
   }
 
   bool handled_exception() const { return handled_exception_; }
 
  private:
   bool handled_exception_;
 };
 
 TEST_F(ModuleSystemTest, TestExceptionHandling) {
@@ skipping 428 matching lines @@
                         "});");
   scoped_ptr<ModuleSystemTestEnvironment> other_env = CreateEnvironment();
   gin::ModuleRegistry::From(env()->context()->v8_context())->AddBuiltinModule(
       env()->isolate(), "natives", other_env->module_system()->NewInstance());
   other_env->ShutdownModuleSystem();
   env()->module_system()->Require("test");
   RunResolvedPromises();
 }
 
 }  // namespace extensions