Reduce how often LayoutSVGShape::updateShapeFromElement is called

Source/core/layout/svg/LayoutSVGShape.cpp

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2005, 2007 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2009 Google, Inc.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  * Copyright (C) 2009 Jeff Schiller <codedread@gmail.com>
  * Copyright (C) 2011 Renata Hodovan <reni@webkit.org>
  * Copyright (C) 2011 University of Szeged
@@ skipping 134 matching lines @@
     } else {
         m_localTransform = 0;
     }
 }
 
 void LayoutSVGShape::layout()
 {
     bool updateCachedBoundariesInParents = false;
     LayoutAnalyzer::Scope analyzer(*this);
 
-    if (m_needsShapeUpdate || m_needsBoundariesUpdate) {
+    if (m_needsBoundariesUpdate && toSVGGeometryElement(element())->selfHasRelativeLengths())
+        m_needsShapeUpdate = true;
+
+    if (m_needsShapeUpdate)
         updateShapeFromElement();

[fs, 2015/06/01 09:09:19]

This also updates m_strokeBoundingBox, so we'll need to split that part out
first (and call it below) before this can work. (This appears to be the reason
for some of the expectation changes.)

-        m_needsShapeUpdate = false;
+
+    if (m_needsBoundariesUpdate || m_needsShapeUpdate) {
         updatePaintInvalidationBoundingBox();
         m_needsBoundariesUpdate = false;
+        m_needsShapeUpdate = false;
         updateCachedBoundariesInParents = true;
     }
 
     if (m_needsTransformUpdate) {
         updateLocalTransform();
         m_needsTransformUpdate = false;
         updateCachedBoundariesInParents = true;
     }
 
     // Invalidate all resources of this client if our layout changed.
@@ skipping 108 matching lines @@
     SVGLayoutSupport::intersectPaintInvalidationRectWithResources(this, m_paintInvalidationBoundingBox);
 }
 
 float LayoutSVGShape::strokeWidth() const
 {
     SVGLengthContext lengthContext(element());
     return lengthContext.valueForLength(style()->svgStyle().strokeWidth());
 }
 
 }