Support piping log data over the service protocol

runtime/lib/developer.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.
 
 patch bool debugger({bool when: true, String msg}) native "Developer_debugger";
 
 patch inspect(object) native "Developer_inspect";
+
+patch log(int sequenceNumber,
+          int millisecondsSinceEpoch,
+          int level,
+          String name,
+          String message,
+          [Zone zone,
+           Object error,
+           StackTrace stackTrace]) native "Developer_log";