Fix virtual/override/final usage in the rest of Source/core/.

Source/core/timing/PerformanceBase.h

 /*
  * Copyright (C) 2010 Google Inc. All rights reserved.
  * Copyright (C) 2012 Intel Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 35 matching lines @@
 class ExceptionState;
 class PerformanceTiming;
 class ResourceTimingInfo;
 class UserTiming;
 
 using PerformanceEntryVector = HeapVector<Member<PerformanceEntry>>;
 
 class CORE_EXPORT PerformanceBase : public RefCountedGarbageCollectedEventTargetWithInlineData<PerformanceBase> {
     REFCOUNTED_GARBAGE_COLLECTED_EVENT_TARGET(PerformanceBase);
 public:
-    virtual ~PerformanceBase();
+    ~PerformanceBase() override;
 
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     virtual PerformanceTiming* timing() const;
     double now() const;
 
     double timeOrigin() const { return m_timeOrigin; }
 
     PerformanceEntryVector getEntries() const;
     PerformanceEntryVector getEntriesByType(const String& entryType);
     PerformanceEntryVector getEntriesByName(const String& name, const String& entryType);
 
@@ skipping 34 matching lines @@
     PerformanceEntryVector m_resourceTimingBuffer;
     unsigned m_resourceTimingBufferSize;
     double m_timeOrigin;
 
     Member<UserTiming> m_userTiming;
 };
 
 } // namespace blink
 
 #endif // PerformanceBase_h