Lazily allocate svg shape transforms, shrink RenderSVGShape by 44B

Source/core/rendering/svg/RenderSVGShape.cpp

Index: Source/core/rendering/svg/RenderSVGShape.cpp
diff --git a/Source/core/rendering/svg/RenderSVGShape.cpp b/Source/core/rendering/svg/RenderSVGShape.cpp
index ba966d95be3449e7eb0e36b9f6a72cebb94d4431..d18edac4a901d29c365a11c1f030131446b14de9 100644
--- a/Source/core/rendering/svg/RenderSVGShape.cpp
+++ b/Source/core/rendering/svg/RenderSVGShape.cpp
@@ -123,7 +123,8 @@ void RenderSVGShape::layout()
     }
 
     if (m_needsTransformUpdate) {
-        m_localTransform =  toSVGGraphicsElement(element())->calculateAnimatedLocalTransform();
+        SVGGraphicsElement* graphicsElement = toSVGGraphicsElement(element());
+        m_localTransform = graphicsElement->hasAnimatedLocalTransform() ? adoptPtr(new AffineTransform(graphicsElement->calculateAnimatedLocalTransform())) : 0;

[fs, 2014/11/05 13:46:47]

It'd be nice to not reallocate the transform for each update, but I suppose a
micro-bench would be needed to even observe it - and we're already assuming that
the transform will rarely be there anyway so probably not worth the additional
code complexity at this point in time.

[f(malita), 2014/11/06 22:16:15]

+1 for avoiding unnecessary reallocations. Even if local transforms are rare for
shapes, we shouldn't penalize outliers.

[pdr., 2014/11/07 04:20:27]

Agreed and done :)

         m_needsTransformUpdate = false;
         updateCachedBoundariesInParents = true;
     }
@@ -175,7 +176,7 @@ bool RenderSVGShape::nodeAtFloatPoint(const HitTestRequest& request, HitTestResu
         return false;
 
     FloatPoint localPoint;
-    if (!SVGRenderSupport::transformToUserSpaceAndCheckClipping(this, m_localTransform, pointInParent, localPoint))
+    if (!SVGRenderSupport::transformToUserSpaceAndCheckClipping(this, localToParentTransform(), pointInParent, localPoint))
         return false;
 
     PointerEventsHitRules hitRules(PointerEventsHitRules::SVG_GEOMETRY_HITTESTING, request, style()->pointerEvents());