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

mojo/dart/embedder/test/dart_to_cpp_tests.dart

Index: mojo/dart/embedder/test/dart_to_cpp_tests.dart
diff --git a/mojo/dart/embedder/test/dart_to_cpp_tests.dart b/mojo/dart/embedder/test/dart_to_cpp_tests.dart
index be7df4c5e1e1874c23bb63f5c52751f9d268a701..81602941b482d2fcc680114574b5dcbc22163001 100644
--- a/mojo/dart/embedder/test/dart_to_cpp_tests.dart
+++ b/mojo/dart/embedder/test/dart_to_cpp_tests.dart
@@ -4,10 +4,10 @@
 
 import 'dart:async';
 import 'dart:typed_data';
-import 'dart:mojo.bindings' as bindings;
-import 'dart:mojo.core' as core;
 
 import 'package:mojo/dart/embedder/test/dart_to_cpp.mojom.dart';
+import 'package:mojo/public/dart/bindings.dart' as bindings;
+import 'package:mojo/public/dart/core.dart' as core;
 
 class DartSideImpl implements DartSide {
   static const int BAD_VALUE = 13;