Reduce how often LayoutSVGShape::updateShapeFromElement is called

Source/core/layout/svg/LayoutSVGShape.cpp

Index: Source/core/layout/svg/LayoutSVGShape.cpp
diff --git a/Source/core/layout/svg/LayoutSVGShape.cpp b/Source/core/layout/svg/LayoutSVGShape.cpp
index f5f47a848267768566bd24f9858ad452e8490d10..61ff20e5a9cb76e739e55f331eb1218a8bf17497 100644
--- a/Source/core/layout/svg/LayoutSVGShape.cpp
+++ b/Source/core/layout/svg/LayoutSVGShape.cpp
@@ -152,11 +152,16 @@ 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;
     }