Remove the concept of user stylesheets.

LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html

Index: LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html
diff --git a/LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html b/LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html
index b69b7c4d7c81a49a43248ee8664938ad91206665..cfdbef543bac4cf7cf942633ec09de4630e3cffc 100644
--- a/LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html
+++ b/LayoutTests/css3/device-adapt/viewport-width-extend-to-zoom.html
@@ -14,7 +14,7 @@
         }, "Check that window.testRunner is present. Required to add a user stylesheet.");
 
         if (window.testRunner) {
-            testRunner.addUserStyleSheet("@viewport { width: -internal-extend-to-zoom 980px; min-zoom: 0.25; max-zoom: 5; height: auto; zoom: auto; user-zoom: zoom; orientation: auto }", true);
+            testRunner.injectStyleSheet("@viewport { width: -internal-extend-to-zoom 980px; min-zoom: 0.25; max-zoom: 5; height: auto; zoom: auto; user-zoom: zoom; orientation: auto }", true);
         }
     </script>
 </head>