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

Source/modules/encryptedmedia/SimpleContentDecryptionModuleResultPromise.h

 // 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.
 
 #ifndef SimpleContentDecryptionModuleResultPromise_h
 #define SimpleContentDecryptionModuleResultPromise_h
 
 #include "modules/encryptedmedia/ContentDecryptionModuleResultPromise.h"
 
 namespace blink {
 
 // This class creates a simple ContentDecryptionModuleResultPromise where the
 // implementation of complete() will resolve the promise with void. All other
 // complete() methods are not expected to be called (and will reject the
 // promise).
 class SimpleContentDecryptionModuleResultPromise : public ContentDecryptionModuleResultPromise {
 public:
     explicit SimpleContentDecryptionModuleResultPromise(ScriptState*);
-    virtual ~SimpleContentDecryptionModuleResultPromise();
+    ~SimpleContentDecryptionModuleResultPromise() override;
 
     // ContentDecryptionModuleResultPromise implementation.
-    virtual void complete() override;
+    void complete() override;
 };
 
 } // namespace blink
 
 #endif // SimpleContentDecryptionModuleResultPromise_h