Support piping log data over the service protocol

runtime/observatory/tests/service/logging_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=--compile_all --error_on_bad_type --error_on_bad_override
+
+import 'dart:developer' as developer;
+import 'package:observatory/service_io.dart';
+import 'package:unittest/unittest.dart';
+import 'package:logging/logging.dart';
+
+import 'test_helper.dart';
+
+void init() {
+  Logger.root.level = Level.ALL;
+  Logger.root.onRecord.listen(developer.logOnRecord);
+}
+
+void run() {
+  developer.debugger();
+  Logger.root.fine('Hey Buddy!');
+  developer.debugger();
+  Logger.root.info('YES');
+}
+
+var tests = [
+  hasStoppedAtBreakpoint,
+  resumeIsolateAndAwaitEvent(Isolate.kLoggingStream, (ServiceEvent event) {
+    expect(event.kind, equals(ServiceEvent.kLogging));
+    expect(event.logRecord['sequenceNumber'], equals(0));
+    expect(event.logRecord['message'].valueAsString, equals('Hey Buddy!'));
+    expect(event.logRecord['level'], equals(Level.FINE));
+    expect(event.logRecord['time'], new isInstanceOf<DateTime>());
+  }),
+  resumeIsolateAndAwaitEvent(Isolate.kLoggingStream, (ServiceEvent event) {
+    expect(event.kind, equals(ServiceEvent.kLogging));
+    expect(event.logRecord['sequenceNumber'], equals(1));
+    expect(event.logRecord['level'], equals(Level.INFO));
+    expect(event.logRecord['message'].valueAsString, equals('YES'));
+    expect(event.logRecord['time'], new isInstanceOf<DateTime>());
+  }),
+];
+
+main(args) => runIsolateTests(args,
+                              tests,
+                              testeeBefore: init,
+                              testeeConcurrent: run);