Update references to Mojo core and bindings

sky/framework/shell.dart

Index: sky/framework/shell.dart
diff --git a/sky/framework/shell.dart b/sky/framework/shell.dart
index a38f8fbd2d865d01ba15014238fc2eb03bf69190..86a71a4c229cb75918edbbb6a10afd24f9b9390e 100644
--- a/sky/framework/shell.dart
+++ b/sky/framework/shell.dart
@@ -2,10 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import "package:mojo/public/dart/application.dart";
 import "dart:sky.internals" as internals;
-import "dart:mojo.core" as core;
+import "package:mojo/public/dart/application.dart";
 import "package:mojo/public/interfaces/application/service_provider.mojom.dart";
+import 'package:mojo/public/dart/core.dart' as core;
 
 ApplicationConnection _initConnection() {
   int rawHandle = internals.takeServicesProvidedByEmbedder();