BackgroundImage incorrectly returns empty url() when created on-the-fly

LayoutTests/fast/css/uri-token-parsing-expected.txt

 Test parsing of CSS URI tokens. Older versions of WebKit did some double processing of these, hence this test would have failed.
 
 SUCCESS
 
 Rules from the stylesheet:
 
 #a { content: url(c); }
 #b { content: url(d); }
 #c { content: url(e); }
 #d { content: url(f); }
 #f { content: url(c); }
-#g { content: url(d); }
-#h { content: url(e); }
-#i { content: url(f); }
+#g { content: url(' d'); }
+#h { content: url('e '); }
+#i { content: url(' f '); }
 #j { content: url('url(g)'); }
 #l { content: url(c); }
-#m { content: url(d); }
-#n { content: url(e); }
-#o { content: url(f); }
+#m { content: url(' d'); }
+#n { content: url('e '); }
+#o { content: url(' f '); }
 #p { content: url('url(g)'); }
 #q { cursor: url('url(q)'), pointer; }
 #r { list-style-image: url('url(r)'); }
 #s { background-image: url('url(s)'); }
 #t { -webkit-mask-image: url('url(t)'); }
 #u { -webkit-border-image: url('url(u)') 1 2 3 4 fill stretch round; }
 #v { -webkit-mask-box-image-source: url('url(v)'); }
-#w { content: url(ww); }
-#x { content: url(x%20xx); }
-#y { content: url(y%20yy); }
+#w { content: url('w\\d w'); }
+#x { content: url(' x x\\9 x '); }
+#y { content: url('y y\\9 y'); }
 Expected result:
 
 #a { content: url(c); }
 #b { content: url(d); }
 #c { content: url(e); }
 #d { content: url(f); }
 #f { content: url(c); }
-#g { content: url(d); }
-#h { content: url(e); }
-#i { content: url(f); }
+#g { content: url(' d'); }
+#h { content: url('e '); }
+#i { content: url(' f '); }
 #j { content: url('url(g)'); }
 #l { content: url(c); }
-#m { content: url(d); }
-#n { content: url(e); }
-#o { content: url(f); }
+#m { content: url(' d'); }
+#n { content: url('e '); }
+#o { content: url(' f '); }
 #p { content: url('url(g)'); }
 #q { cursor: url('url(q)'), pointer; }
 #r { list-style-image: url('url(r)'); }
 #s { background-image: url('url(s)'); }
 #t { -webkit-mask-image: url('url(t)'); }
 #u { -webkit-border-image: url('url(u)') 1 2 3 4 fill stretch round; }
 #v { -webkit-mask-box-image-source: url('url(v)'); }
-#w { content: url(ww); }
-#x { content: url(x%20xx); }
-#y { content: url(y%20yy); }
+#w { content: url('w\\d w'); }
+#x { content: url(' x x\\9 x '); }
+#y { content: url('y y\\9 y'); }