Reapply "[vm] Don't enable the profiler by default. Enable the profiler at startup with --observe, …

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 116 matching lines @@
     var fullArgs = [];
     if (pause_on_start) {
       fullArgs.add('--pause-isolates-on-start');
     }
     if (pause_on_exit) {
       fullArgs.add('--pause-isolates-on-exit');
     }
     if (pause_on_unhandled_exceptions) {
       fullArgs.add('--pause-isolates-on-unhandled-exceptions');
     }
+    fullArgs.add('--profiler');
     if (extraArgs != null) {
       fullArgs.addAll(extraArgs);
     }
 
     fullArgs.addAll(Platform.executableArguments);
     if (!testeeControlsServer) {
       fullArgs.add('--enable-vm-service:0');
     }
     fullArgs.addAll(args);
 
@@ skipping 16 matching lines @@
     if (pause_on_start) {
       dartFlags.add('--pause_isolates_on_start');
       fullArgs.add('--start-paused');
     }
     if (pause_on_exit) {
       dartFlags.add('--pause_isolates_on_exit');
     }
     if (pause_on_unhandled_exceptions) {
       dartFlags.add('--pause_isolates_on_unhandled_exceptions');
     }
+    dartFlags.add('--profiler');
     // Override mirrors.
     dartFlags.add('--enable_mirrors=true');
     if (extraArgs != null) {
       fullArgs.addAll(extraArgs);
     }
 
     fullArgs.addAll(Platform.executableArguments);
     if (!testeeControlsServer) {
       fullArgs.add('--observatory-port=0');
     }
@@ skipping 296 matching lines @@
     new _ServiceTesterRunner().run(
         mainArgs: mainArgs,
         extraArgs: extraArgs,
         vmTests: tests,
         pause_on_start: pause_on_start,
         pause_on_exit: pause_on_exit,
         verbose_vm: verbose_vm,
         pause_on_unhandled_exceptions: pause_on_unhandled_exceptions);
   }
 }