Fix virtual/override/final usage in Source/core/html/.

Source/core/html/LinkManifest.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 LinkManifest_h
 #define LinkManifest_h
 
 #include "core/html/LinkResource.h"
 #include "wtf/FastAllocBase.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/RefPtr.h"
 
 namespace blink {
 
 class HTMLLinkElement;
 
 class LinkManifest final : public LinkResource {
     WTF_MAKE_FAST_ALLOCATED_WILL_BE_REMOVED(LinkManifest);
 public:
 
     static PassOwnPtrWillBeRawPtr<LinkManifest> create(HTMLLinkElement* owner);
 
-    virtual ~LinkManifest();
+    ~LinkManifest() override;
 
     // LinkResource
-    virtual void process() override;
-    virtual Type type() const override { return Manifest; }
-    virtual bool hasLoaded() const override;
-    virtual void ownerRemoved() override;
+    void process() override;
+    Type type() const override { return Manifest; }
+    bool hasLoaded() const override;
+    void ownerRemoved() override;
 
 private:
     explicit LinkManifest(HTMLLinkElement* owner);
 };
 
 }
 
 #endif // LinkManifest_h