Make LayoutSVGViewportContainer <-> SVGSVGElement association obvious

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

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 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.
  *
  * 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.
  */
 
 #include "core/layout/svg/LayoutSVGViewportContainer.h"
 
 #include "core/layout/svg/SVGLayoutSupport.h"
-#include "core/paint/SVGContainerPainter.h"
 #include "core/svg/SVGSVGElement.h"
-#include "core/svg/SVGUseElement.h"
-#include "platform/graphics/GraphicsContext.h"
 
 namespace blink {
 
-LayoutSVGViewportContainer::LayoutSVGViewportContainer(SVGElement* node)
+LayoutSVGViewportContainer::LayoutSVGViewportContainer(SVGSVGElement* node)
     : LayoutSVGContainer(node),
       m_isLayoutSizeChanged(false),
       m_needsTransformUpdate(true) {}
 
 void LayoutSVGViewportContainer::determineIfLayoutSizeChanged() {
-  ASSERT(element());
-  if (!isSVGSVGElement(*element()))
-    return;
-
+  DCHECK(isSVGSVGElement(element()));
   m_isLayoutSizeChanged =
       toSVGSVGElement(element())->hasRelativeLengths() && selfNeedsLayout();
 }
 
 void LayoutSVGViewportContainer::setNeedsTransformUpdate() {
   setMayNeedPaintInvalidationSubtree();
   if (RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled()) {
     // The transform paint property relies on the SVG transform being up-to-date
     // (see: PaintPropertyTreeBuilder::updateTransformForNonRootSVG).
     setNeedsPaintPropertyUpdate();
@@ skipping 36 matching lines @@
     HitTestAction action) {
   // Respect the viewport clip which is in parent coordinates.
   if (SVGLayoutSupport::isOverflowHidden(this)) {
     if (!m_viewport.contains(pointInParent))
       return false;
   }
   return LayoutSVGContainer::nodeAtFloatPoint(result, pointInParent, action);
 }
 
 }  // namespace blink