Bug 682411 - Filters on shapes that have zero width or height assert. r=roc

layout/svg/base/src/nsSVGFilterFrame.cpp

@@ -143,6 +143,10 @@ nsAutoFilterInstance::nsAutoFilterInstance(nsIFrame *aTarget,
   }
 
   gfxMatrix userToDeviceSpace = nsSVGUtils::GetCanvasTM(aTarget);
+  if (userToDeviceSpace.IsSingular()) {
+    // nothing to draw
+    return;
+  }
   
   // Calculate filterRes (the width and height of the pixel buffer of the
   // temporary offscreen surface that we'll paint into):

layout/svg/crashtests/682411-1.svg

@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="Windows-1252"?>
+<svg xmlns="http://www.w3.org/2000/svg" style="width: 0pt; padding: 100px;">
+  <filter id="s"/>
+  <g filter="url(#s)"><text>z</text></g>
+</svg>

layout/svg/crashtests/crashtests.list

@@ -115,3 +115,4 @@ load 655025-3.svg
 load 657077-1.svg
 load 669025-1.svg
 load 669025-2.svg
+load 682411-1.svg