Remove polyfill for WebGLVertexArrayObjectOES that adds 200ms to startup.

lib/runtime/dart_library.js

Index: lib/runtime/dart_library.js
diff --git a/lib/runtime/dart_library.js b/lib/runtime/dart_library.js
index 134c948ac175358086269a42f60bf1316181f669..6a1345726ec32c4e2246d6bbc2f38b8d9a9a2566 100644
--- a/lib/runtime/dart_library.js
+++ b/lib/runtime/dart_library.js
@@ -138,14 +138,6 @@ var dart_library =
         let d = document.createElement('div');
         window.Animation = d.animate(d).constructor;
       }
-      if (typeof WebGLVertexArrayObjectOES == "undefined") {
-        let context = document.createElement('canvas').getContext('webgl');
-        if (context) {
-          window.WebGLVertexArrayObjectOES =
-              context.getExtension("OES_vertex_array_object")
-                     .createVertexArrayOES().constructor;
-        }
-      }
     }
 
     // This import is only needed for chrome debugging. We should provide an