Update remaining core classes to use OVERRIDE / FINAL when needed

Source/core/plugins/DOMMimeType.h

Index: Source/core/plugins/DOMMimeType.h
diff --git a/Source/core/plugins/DOMMimeType.h b/Source/core/plugins/DOMMimeType.h
index 8670725b7171c40782d4e40f09aa7977c366f63d..7d6c13885fe7f90f1056b038b4890a57b2b6434a 100644
--- a/Source/core/plugins/DOMMimeType.h
+++ b/Source/core/plugins/DOMMimeType.h
@@ -33,14 +33,14 @@ namespace WebCore {
 class DOMPlugin;
 class Frame;
 
-class DOMMimeType : public RefCounted<DOMMimeType>, public ScriptWrappable, public FrameDestructionObserver {
+class DOMMimeType FINAL : public RefCounted<DOMMimeType>, public ScriptWrappable, public FrameDestructionObserver {
 public:
     static PassRefPtr<DOMMimeType> create(PassRefPtr<PluginData> pluginData, Frame* frame, unsigned index) { return adoptRef(new DOMMimeType(pluginData, frame, index)); }
-    ~DOMMimeType();
+    virtual ~DOMMimeType();
 
-    const String &type() const;
+    const String& type() const;
     String suffixes() const;
-    const String &description() const;
+    const String& description() const;
     PassRefPtr<DOMPlugin> enabledPlugin() const;
 
 private: