Turn on service tracing for all service tests.

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 15 matching lines @@
                             Platform.script.toFilePath(),
                             _TESTEE_MODE_FLAG] {}
 
   Future<int> launch(bool pause_on_start,
                      bool pause_on_exit,
                      bool pause_on_unhandled_exceptions,
                      bool trace_service) {
     assert(pause_on_start != null);
     assert(pause_on_exit != null);
     assert(trace_service != null);
+    // TODO(turnidge): I have temporarily turned on service tracing for
+    // all tests to help diagnose flaky tests.
+    trace_service = true;
     String dartExecutable = Platform.executable;
     var fullArgs = [];
     if (trace_service) {
       fullArgs.add('--trace-service');
     }
     if (pause_on_start) {
       fullArgs.add('--pause-isolates-on-start');
     }
     if (pause_on_exit) {
       fullArgs.add('--pause-isolates-on-exit');
@@ skipping 227 matching lines @@
 
 Future<Isolate> hasStoppedAtBreakpoint(Isolate isolate) {
   return hasPausedFor(isolate, ServiceEvent.kPauseBreakpoint);
 }
 
 Future<Isolate> hasStoppedWithUnhandledException(Isolate isolate) {
   return hasPausedFor(isolate, ServiceEvent.kPauseException);
 }
 
 Future<Isolate> hasPausedAtStart(Isolate isolate) {
-  // Set up a listener to wait for breakpoint events.
-  Completer completer = new Completer();
-  isolate.vm.getEventStream(VM.kDebugStream).then((stream) {
-    var subscription;
-    subscription = stream.listen((ServiceEvent event) {
-        if (event.kind == ServiceEvent.kPauseStart) {
-          print('Paused at isolate start');
-          subscription.cancel();
-          if (completer != null) {
-            // Reload to update isolate.pauseEvent.
-            completer.complete(isolate.reload());
-            completer = null;
-          }
-        }
-    });
-
-    // Pause may have happened before we subscribed.
-    isolate.reload().then((_) {
-      if ((isolate.pauseEvent != null) &&
-         (isolate.pauseEvent.kind == ServiceEvent.kPauseStart)) {
-        print('Paused at isolate start');
-        subscription.cancel();
-        if (completer != null) {
-          completer.complete(isolate);
-          completer = null;
-        }
-      }
-    });
-  });
-
-  return completer.future;
+  return hasPausedFor(isolate, ServiceEvent.kPauseStart);
 }
 
-
 // Currying is your friend.
 IsolateTest setBreakpointAtLine(int line) {
   return (Isolate isolate) async {
     print("Setting breakpoint for line $line");
     Library lib = await isolate.rootLibrary.load();
     Script script = lib.scripts.single;
 
     Breakpoint bpt = await isolate.addBreakpoint(script, line);
     print("Breakpoint is $bpt");
     expect(bpt, isNotNull);
@@ skipping 142 matching lines @@
       }, onError: (e, st) {
         process.requestExit();
         if (!_isWebSocketDisconnect(e)) {
           print('Unexpected exception in service tests: $e $st');
           throw e;
         }
       });
     });
   }
 }