Update remaining core classes to use OVERRIDE / FINAL when needed

Source/core/timing/Performance.h

Index: Source/core/timing/Performance.h
diff --git a/Source/core/timing/Performance.h b/Source/core/timing/Performance.h
index 8dfe0be352cd1bfafa340c02f3b4735d88c1a2ad..65111a625984e864ee28d219d721a138a813a082 100644
--- a/Source/core/timing/Performance.h
+++ b/Source/core/timing/Performance.h
@@ -53,11 +53,11 @@ class ResourceResponse;
 class ResourceTimingInfo;
 class UserTiming;
 
-class Performance : public ScriptWrappable, public RefCounted<Performance>, public DOMWindowProperty, public EventTargetWithInlineData {
+class Performance FINAL : public ScriptWrappable, public RefCounted<Performance>, public DOMWindowProperty, public EventTargetWithInlineData {
     REFCOUNTED_EVENT_TARGET(Performance);
 public:
     static PassRefPtr<Performance> create(Frame* frame) { return adoptRef(new Performance(frame)); }
-    ~Performance();
+    virtual ~Performance();
 
     virtual const AtomicString& interfaceName() const OVERRIDE;
     virtual ExecutionContext* executionContext() const OVERRIDE;