Fix virtual/override/final usage in Source/modules/.

Source/modules/InitModules.h

 // Copyright (c) 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.
 
 #ifndef InitModules_h
 #define InitModules_h
 
 #include "core/Init.h"
 #include "modules/ModulesExport.h"
 
 namespace blink {
 
 class MODULES_EXPORT ModulesInitializer : public CoreInitializer {
 public:
-    virtual void init() override;
+    void init() override;
     static void terminateThreads();
 };
 
 } // namespace blink
 
 #endif // InitModules_h