Avoid layout/full-repaint on view height change if possible

Source/core/rendering/svg/RenderSVGRoot.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007, 2008, 2009 Rob Buis <buis@kde.org>
  * Copyright (C) 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.
  * Copyright (C) Research In Motion Limited 2011. 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
@@ skipping 155 matching lines @@
         return m_containerSize.height();
 
     if (style()->logicalHeight().isSpecified() || style()->logicalMaxHeight().isSpecified())
         return RenderReplaced::computeReplacedLogicalHeight();
 
     if (svg->heightAttributeEstablishesViewport()) {
         Length height = svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties);
         if (height.isPercent()) {
             RenderBlock* cb = containingBlock();
             ASSERT(cb);
-            while (cb->isAnonymous()) {
+            while (cb->isAnonymous())
                 cb = cb->containingBlock();
-                cb->addPercentHeightDescendant(const_cast<RenderSVGRoot*>(this));
-            }
+            cb->addPercentHeightDescendant(const_cast<RenderSVGRoot*>(this));

[ojan, 2013/12/18 00:48:20]

Ditto the other comment. Don't see why this is correct.

         } else
             RenderBlock::removePercentHeightDescendant(const_cast<RenderSVGRoot*>(this));
 
         return resolveLengthAttributeForSVG(height, style()->effectiveZoom(), containingBlock()->availableLogicalHeight(IncludeMarginBorderPadding), view());
     }
 
     // SVG embedded through object/embed/iframe.
     if (isEmbeddedThroughFrameContainingSVGDocument())
         return document().frame()->ownerRenderer()->availableLogicalHeight(IncludeMarginBorderPadding);
 
@@ skipping 255 matching lines @@
 
 bool RenderSVGRoot::hasRelativeLogicalHeight() const
 {
     SVGSVGElement* svg = toSVGSVGElement(node());
     ASSERT(svg);
 
     return svg->intrinsicHeight(SVGSVGElement::IgnoreCSSProperties).isPercent();
 }
 
 }