Rate limit devfs writes

runtime/observatory/tests/service/test_helper.dart

 // Copyright (c) 2013, 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.
 
 library test_helper;
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'package:observatory/service_io.dart';
@@ skipping 84 matching lines @@
                                 bool pause_on_exit,
                                 bool pause_on_unhandled_exceptions,
                                 bool trace_service,
                                 bool trace_compiler) {
     assert(pause_on_start != null);
     assert(pause_on_exit != null);
     assert(pause_on_unhandled_exceptions != null);
     assert(trace_service != null);
     assert(trace_compiler != null);
 
-    // TODO(turnidge): I have temporarily turned on service tracing for
-    // all tests to help diagnose flaky tests.
-    trace_service = true;
-
     if (_shouldLaunchSkyShell()) {
       return _spawnSkyProcess(pause_on_start,
                               pause_on_exit,
                               pause_on_unhandled_exceptions,
                               trace_service,
                               trace_compiler);
     } else {
       return _spawnDartProcess(pause_on_start,
                                pause_on_exit,
                                pause_on_unhandled_exceptions,
@@ skipping 364 matching lines @@
         mainArgs: mainArgs,
         vmTests: tests,
         pause_on_start: pause_on_start,
         pause_on_exit: pause_on_exit,
         trace_service: trace_service,
         trace_compiler: trace_compiler,
         verbose_vm: verbose_vm,
         pause_on_unhandled_exceptions: pause_on_unhandled_exceptions);
   }
 }