Dart: Removes all but native calls and the handle watcher from the snapshot.

mojo/dart/test/import_mojo.dart

Index: mojo/dart/test/import_mojo.dart
diff --git a/mojo/dart/test/import_mojo.dart b/mojo/dart/test/import_mojo.dart
index 14fed46f3311c339f8fedcf40527d7e31b070ba1..6e7ff483a5a7bd7f9cf0865f58a64fd03cbb151b 100644
--- a/mojo/dart/test/import_mojo.dart
+++ b/mojo/dart/test/import_mojo.dart
@@ -2,11 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'dart:mojo.bindings';
-import 'dart:mojo.core';
+import 'package:mojo/public/dart/bindings.dart' as bindings;
+import 'package:mojo/public/dart/core.dart' as core;
 
 main() {
-  MojoMessagePipe pipe = new MojoMessagePipe();
+  core.MojoMessagePipe pipe = new core.MojoMessagePipe();
   pipe.endpoints[0].handle.close();
   pipe.endpoints[1].handle.close();
 }