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

Source/modules/serviceworkers/StashedMessagePort.h

 // Copyright 2015 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 StashedMessagePort_h
 #define StashedMessagePort_h
 
 #include "bindings/core/v8/ScriptWrappable.h"
 #include "core/dom/MessagePort.h"
 #include "modules/ModulesExport.h"
 
 namespace blink {
 class ExecutionContext;
 class StashedMessagePort;
 
 using StashedMessagePortArray = HeapVector<Member<StashedMessagePort>, 1>;
 
 // Represents a message port that has been stashed. Overrides messageAvailable
 // to dispatch messages as a global event instead of as events on this port.
 class MODULES_EXPORT StashedMessagePort final : public MessagePort {
     DEFINE_WRAPPERTYPEINFO();
     WTF_MAKE_NONCOPYABLE(StashedMessagePort);
 public:
     static StashedMessagePort* create(ExecutionContext&, PassOwnPtr<WebMessagePortChannel>, const String& name);
-    virtual ~StashedMessagePort();
+    ~StashedMessagePort() override;
 
     static StashedMessagePortArray* toStashedMessagePortArray(ExecutionContext*, const WebMessagePortChannelArray&, const WebVector<WebString>& channelKeys);
 
     // StashedMessagePort.idl
     String name() const;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { MessagePort::trace(visitor); }
 
 private:
     StashedMessagePort(ExecutionContext&, PassOwnPtr<WebMessagePortChannel>, const String& name);
 
     void messageAvailable() override;
     void dispatchMessages();
 
     String m_name;
     WeakPtrFactory<StashedMessagePort> m_weakFactory;
 };
 
 } // namespace blink
 
 #endif // StashedMessagePort_h