Implement interfaces in PaintInfo and make it a class.

Source/core/rendering/svg/RenderSVGViewportContainer.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.
@@ skipping 33 matching lines @@
 {
     if (!node()->hasTagName(SVGNames::svgTag))
         return;
 
     m_isLayoutSizeChanged = toSVGSVGElement(node())->hasRelativeLengths() && selfNeedsLayout();
 }
 
 void RenderSVGViewportContainer::applyViewportClip(PaintInfo& paintInfo)
 {
     if (SVGRenderSupport::isOverflowHidden(this))
-        paintInfo.context->clip(m_viewport);
+        paintInfo.getContext()->clip(m_viewport);
 }
 
 void RenderSVGViewportContainer::calcViewport()
 {
     SVGElement* element = toSVGElement(node());
     if (!element->hasTagName(SVGNames::svgTag))
         return;
     SVGSVGElement* svg = toSVGSVGElement(element);
     FloatRect oldViewport = m_viewport;
 
@@ skipping 87 matching lines @@
     // An empty viewBox disables rendering.
     if (node()->hasTagName(SVGNames::svgTag)) {
         if (toSVGSVGElement(node())->hasEmptyViewBox())
             return;
     }
 
     RenderSVGContainer::paint(paintInfo, paintOffset);
 }
 
 }