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

mojo/dart/test/validation_test.dart

Index: mojo/dart/test/validation_test.dart
diff --git a/mojo/dart/test/validation_test.dart b/mojo/dart/test/validation_test.dart
index 35070889a77d53c74acaf6229f8a45c3579f8c2c..0c594ed11dfe72f60159fd44138b0ab4bfaa15c3 100644
--- a/mojo/dart/test/validation_test.dart
+++ b/mojo/dart/test/validation_test.dart
@@ -5,13 +5,13 @@
 import 'dart:async';
 import 'dart:convert';
 import 'dart:isolate';
-import 'dart:typed_data';
-import 'dart:mojo.bindings';
 import 'dart:mojo.builtin' as builtin;
-import 'dart:mojo.core';
+import 'dart:typed_data';
 
 import 'package:mojo/dart/testing/validation_test_input_parser.dart' as parser;
 import 'package:mojo/public/interfaces/bindings/tests/validation_test_interfaces.mojom.dart';
+import 'package:mojo/public/dart/bindings.dart';
+import 'package:mojo/public/dart/core.dart';
 
 class ConformanceTestInterfaceImpl implements ConformanceTestInterface {
   ConformanceTestInterfaceStub _stub;