Update webrender + shaders.

components/servo/lib.rs

@@ -156,6 +156,8 @@ impl<Window> Browser<Window> where Window: WindowMethods + 'static {
                         enable_profiler: opts.webrender_stats,
                         debug: opts.webrender_debug,
                         enable_recording: false,
+                        precache_shaders: opts.precache_shaders,
+                        enable_scrollbars: opts.output_file.is_none(),
                     });
                 (Some(webrender), Some(webrender_sender))
             } else {