Bug 874487 - Have nsSVGUseFrame notify any rendering observers when the referenced element is re-cloned. r=roc

layout/svg/nsSVGUseFrame.cpp

@@ -227,6 +227,7 @@ nsSVGUseFrame::CreateAnonymousContent(nsTArray<ContentInfo>& aElements)
   SVGUseElement *use = static_cast<SVGUseElement*>(mContent);
 
   nsIContent* clone = use->CreateAnonymousContent();
+  nsSVGEffects::InvalidateRenderingObservers(this);
   if (!clone)
     return NS_ERROR_FAILURE;
   if (!aElements.AppendElement(clone))