Timeline service protocol support with Observatory UI

runtime/observatory/tests/service/get_vm_timeline_rpc_test.dart

+// Copyright (c) 2015, 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=--error_on_bad_type --error_on_bad_override --complete_timeline
+
+import 'dart:developer';
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+
+import 'test_helper.dart';
+
+primeTimeline() {
+  Timeline.startSync('apple');
+  Timeline.finishSync();
+}
+
+List<Map> filterForDartEvents(List<Map> events) {
+  return events.where((event) => event['cat'] == 'Dart').toList();
+}
+
+var tests = [
+  (VM vm) async {
+    Map result = await vm.invokeRpcNoUpgrade('_getVMTimeline', {});
+    expect(result['type'], equals('_Timeline'));
+    expect(result['traceEvents'], new isInstanceOf<List>());
+    List<Map> dartEvents = filterForDartEvents(result['traceEvents']);
+    expect(dartEvents.length, equals(1));
+    Map dartEvent = dartEvents[0];
+    expect(dartEvent['name'], equals('apple'));
+  },
+];
+
+main(args) async => runVMTests(args, tests, testeeBefore: primeTimeline);