Make LayoutSVGViewportContainer <-> SVGSVGElement association obvious

third_party/WebKit/Source/core/layout/svg/LayoutSVGViewportContainer.h

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Google, Inc.
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef LayoutSVGViewportContainer_h
 #define LayoutSVGViewportContainer_h
 
 #include "core/layout/svg/LayoutSVGContainer.h"
 
 namespace blink {
 
+class SVGSVGElement;
+
 // This is used for non-root <svg> elements which are SVGTransformable thus we
 // inherit from LayoutSVGContainer instead of LayoutSVGTransformableContainer.
 class LayoutSVGViewportContainer final : public LayoutSVGContainer {
  public:
-  explicit LayoutSVGViewportContainer(SVGElement*);
+  explicit LayoutSVGViewportContainer(SVGSVGElement*);
   FloatRect viewport() const { return m_viewport; }
 
   bool isLayoutSizeChanged() const { return m_isLayoutSizeChanged; }
 
   void determineIfLayoutSizeChanged() override;
   void setNeedsTransformUpdate() override;
 
   const char* name() const override { return "LayoutSVGViewportContainer"; }
 
  private:
@@ skipping 17 matching lines @@
   bool m_isLayoutSizeChanged : 1;
   bool m_needsTransformUpdate : 1;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutSVGViewportContainer,
                                 isSVGViewportContainer());
 
 }  // namespace blink
 
 #endif  // LayoutSVGViewportContainer_h