Rework error handling in the service protocol and in Observatory.

runtime/observatory/tests/service/bad_web_socket_address_test.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // VMOptions=--compile-all --error_on_bad_type --error_on_bad_override
 
+import 'package:logging/logging.dart';
 import "package:observatory/service_io.dart";
 import 'package:unittest/unittest.dart';
 
 void testBadWebSocket() {
   var vm = new WebSocketVM(new WebSocketVMTarget('ws://karatekid/ws'));
   vm.load().catchError(expectAsync((error) {
-        expect(error is ServiceException, isTrue);
-      }));
+    expect(error, new isInstanceOf<NetworkRpcException>());
+  }));
 }
 
 main() {
+  Logger.root.level = Level.INFO;
+  Logger.root.onRecord.listen((LogRecord rec) {

[Cutch, 2015/05/13 17:50:09]

Should this log setup code be inside test_helper?

[turnidge, 2015/05/14 17:53:43]

This test doesn't use test_helper.

+    print('${rec.level.name}: ${rec.time}: ${rec.message}');
+  });
+
   test('bad web socket address', testBadWebSocket);
 }