Remove some dead code in SVG "mixins"

third_party/WebKit/Source/core/svg/SVGSVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2010 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Google, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 24 matching lines @@
 #include "core/events/EventListener.h"
 #include "core/frame/LocalFrame.h"
 #include "core/page/FrameTree.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/UseCounter.h"
 #include "core/layout/LayoutObject.h"
 #include "core/layout/svg/LayoutSVGModelObject.h"
 #include "core/layout/svg/LayoutSVGRoot.h"
 #include "core/layout/svg/LayoutSVGViewportContainer.h"
 #include "core/svg/SVGAngleTearOff.h"
+#include "core/svg/SVGDocumentExtensions.h"
 #include "core/svg/SVGNumberTearOff.h"
 #include "core/svg/SVGPreserveAspectRatio.h"
 #include "core/svg/SVGRectTearOff.h"
 #include "core/svg/SVGTransform.h"
 #include "core/svg/SVGTransformList.h"
 #include "core/svg/SVGTransformTearOff.h"
 #include "core/svg/SVGViewElement.h"
 #include "core/svg/SVGViewSpec.h"
 #include "core/svg/animation/SMILTimeContainer.h"
 #include "platform/FloatConversion.h"
@@ skipping 713 matching lines @@
     visitor->trace(m_width);
     visitor->trace(m_height);
     visitor->trace(m_translation);
     visitor->trace(m_timeContainer);
     visitor->trace(m_viewSpec);
     SVGGraphicsElement::trace(visitor);
     SVGFitToViewBox::trace(visitor);
 }
 
 } // namespace blink