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

Source/core/plugins/testing/DocumentFragmentPluginPlaceholder.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 DocumentFragmentPluginPlaceholder_h
 #define DocumentFragmentPluginPlaceholder_h
 
 #include "core/dom/Document.h"
 #include "core/dom/DocumentFragment.h"
 #include "core/plugins/PluginPlaceholder.h"
 
 namespace blink {
 
 // Populates plugin placeholder content with a document fragment.
 // Used for layout tests that contain a <template>.
 class DocumentFragmentPluginPlaceholder : public NoBaseWillBeGarbageCollected<DocumentFragmentPluginPlaceholder>, public PluginPlaceholder {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(DocumentFragmentPluginPlaceholder);
 public:
     static PassOwnPtrWillBeRawPtr<DocumentFragmentPluginPlaceholder> create(PassRefPtrWillBeRawPtr<DocumentFragment> fragment)
     {
         return adoptPtrWillBeNoop(new DocumentFragmentPluginPlaceholder(fragment));
     }
 
 #if !ENABLE(OILPAN)
-    virtual ~DocumentFragmentPluginPlaceholder() override { }
+    ~DocumentFragmentPluginPlaceholder() override { }
 #endif
     DEFINE_INLINE_VIRTUAL_TRACE() { visitor->trace(m_fragment); }
 
-    virtual void loadIntoContainer(ContainerNode& container) override
+    void loadIntoContainer(ContainerNode& container) override
     {
         RefPtrWillBeRawPtr<Node> clonedFragment = container.document().importNode(m_fragment.get(), true /* deep */, ASSERT_NO_EXCEPTION);
         container.appendChild(clonedFragment.release(), ASSERT_NO_EXCEPTION);
     }
 
 private:
     DocumentFragmentPluginPlaceholder(PassRefPtrWillBeRawPtr<DocumentFragment> fragment) : m_fragment(fragment) { }
 
     RefPtrWillBeMember<DocumentFragment> m_fragment;
 };
 
 } // namespace blink
 
 #endif // DocumentFragmentPluginPlaceholder_h