Fix computation of local-to-border-box transform for RenderSVGRoot

Source/core/rendering/svg/RenderSVGRoot.cpp

Index: Source/core/rendering/svg/RenderSVGRoot.cpp
diff --git a/Source/core/rendering/svg/RenderSVGRoot.cpp b/Source/core/rendering/svg/RenderSVGRoot.cpp
index 0416eddc184087846a0976f48300cc2743b85db5..b6540df43943be5839238c9527775c6792ddd968 100644
--- a/Source/core/rendering/svg/RenderSVGRoot.cpp
+++ b/Source/core/rendering/svg/RenderSVGRoot.cpp
@@ -337,7 +337,7 @@ void RenderSVGRoot::buildLocalToBorderBoxTransform()
     FloatPoint translate = svg->currentTranslate();
     LayoutSize borderAndPadding(borderLeft() + paddingLeft(), borderTop() + paddingTop());
     m_localToBorderBoxTransform = svg->viewBoxToViewTransform(contentWidth() / scale, contentHeight() / scale);
-    if (borderAndPadding.isEmpty() && scale == 1 && translate == FloatPoint::zero())
+    if (borderAndPadding.isZero() && scale == 1 && translate == FloatPoint::zero())

[davve, 2014/05/27 09:16:52]

Nit: Would it perhaps be more readable if we instead created the transform and
compared to identity instead?

[fs, 2014/05/27 10:15:31]

Certainly less error-prone at least (slightly more costly, but probably nothing
to worry about in the bigger picture...)

         return;
     m_localToBorderBoxTransform = AffineTransform(scale, 0, 0, scale, borderAndPadding.width() + translate.x(), borderAndPadding.height() + translate.y()) * m_localToBorderBoxTransform;
 }