Have ResizeViewportAnchor derive from GarbageCollected<> only.

third_party/WebKit/Source/web/ResizeViewportAnchor.h

 // Copyright 2015 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 ResizeViewportAnchor_h
 #define ResizeViewportAnchor_h
 
 #include "core/page/Page.h"
+#include "platform/geometry/DoubleSize.h"
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class FrameView;
 
 // This class scrolls the viewports to compensate for bounds clamping caused by
 // viewport size changes.
 //
 // It is needed when the layout viewport grows (causing its own scroll position
 // to be clamped) and also when it shrinks (causing the visual viewport's scroll
 // position to be clamped).
-class ResizeViewportAnchor : public GarbageCollectedFinalized<ResizeViewportAnchor> {
+class ResizeViewportAnchor final : public GarbageCollected<ResizeViewportAnchor> {
     WTF_MAKE_NONCOPYABLE(ResizeViewportAnchor);
 public:
     ResizeViewportAnchor(Page& page)
         : m_page(page)
         , m_scopeCount(0)
     {
     }
 
     class ResizeScope {
         STACK_ALLOCATED();
@@ skipping 27 matching lines @@
     // ResizeScope.  Note that this should NOT include other kinds of scrolling
     // that may occur during layout, such as from ScrollAnchor.
     DoubleSize m_drift;
     Member<Page> m_page;
     int m_scopeCount;
 };
 
 } // namespace blink
 
 #endif // ResizeViewportAnchor_h