Make IsolateWrapper compatible with the 1.11 isolate API changes.

lib/src/util/dart.dart

Index: lib/src/util/dart.dart
diff --git a/lib/src/util/dart.dart b/lib/src/util/dart.dart
index c62bacbfd2f188dee6d2196fe71d6082bcccf1ae..b487af9f90da6c755cc46dff57342c90a7ffb270 100644
--- a/lib/src/util/dart.dart
+++ b/lib/src/util/dart.dart
@@ -26,7 +26,7 @@ import 'remote_exception.dart';
 ///
 /// [packageRoot] controls the package root of the isolate. It may be either a
 /// [String] or a [Uri].
-Future<Isolate> runInIsolate(String code, message, {packageRoot}) {
+Future<IsolateWrapper> runInIsolate(String code, message, {packageRoot}) {
   // TODO(nweiz): load code from a local server rather than from a file.
   var dir = createTempDir();
   var dartPath = p.join(dir, 'runInIsolate.dart');