workaround for smoketest blocker #42686

now we assert and gracefully continue, instead of crashing.
I'll go give this bug to a better owner.  a=brade, r=mscott


git-svn-id: svn://10.0.0.236/trunk@72323 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/view/src/nsScrollPortView.cpp

@@ -249,6 +249,8 @@ NS_IMETHODIMP nsScrollPortView::ScrollTo(nscoord aX, nscoord aY, PRUint32 aUpdat
 
     // make sure the new position in in bounds
 	GetScrolledView(scrolledView);
+	NS_ASSERTION(scrolledView, "no scrolled view");
+	if (!scrolledView) return NS_ERROR_FAILURE;
 	scrolledView->GetDimensions(&scrolledSize.width, &scrolledSize.height);
 
     nsSize portSize;