Make pkg/stack_trace use stack chains.

pkg/scheduled_test/lib/src/schedule.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 schedule;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:stack_trace/stack_trace.dart';
@@ skipping 408 matching lines @@
   Future schedule(fn(), [String description]) {
     if (isRunning) {
       var task = _schedule.currentTask;
       var wrappedFn = () => _schedule.wrapFuture(
           new Future.value().then((_) => fn()));
       if (task == null) return wrappedFn();
       return task.runChild(wrappedFn, description);
     }
 
     var task = new Task(() {
-      return new Future.sync(fn).catchError((e, stackTrace) {
+      return syncFuture(fn).catchError((e, stackTrace) {
         throw new ScheduleError.from(_schedule, e, stackTrace: stackTrace);
       });
     }, description, this);
     _contents.add(task);
     return task.result;
   }
 
   /// Runs all the tasks in this queue in order.
   Future _run() {
     _schedule._currentQueue = this;
@@ skipping 48 matching lines @@
   /// function has been called. It's used to ensure that out-of-band callbacks
   /// are properly handled by the scheduled test.
   Function _wrapAsync(fn(arg), String description) {
     assert(_schedule.state == ScheduleState.SET_UP || isRunning);
 
     // It's possible that the queue timed out before [fn] finished.
     bool _timedOut() =>
       _schedule.currentQueue != this || pendingCallbacks.isEmpty;
 
     _totalCallbacks++;
-    var trace = new Trace.current();
+    var chain = new Chain.current();
     var pendingCallback = new PendingCallback._(() {
       var fullDescription = description;
       if (fullDescription == null) {
         fullDescription = "Out-of-band operation #${_totalCallbacks}";
       }
 
-      var stackString = prefixLines(terseTraceString(trace));
-      fullDescription += "\n\nStack trace:\n$stackString";
+      var stackString = prefixLines(terseTraceString(chain));
+      fullDescription += "\n\nStack chain:\n$stackString";
       return fullDescription;
     });
     _pendingCallbacks.add(pendingCallback);
 
     return (arg) {
       try {
         return fn(arg);
       } catch (e, stackTrace) {
         var error = new ScheduleError.from(
             _schedule, e, stackTrace: stackTrace);
@@ skipping 92 matching lines @@
   /// The string description of the callback.
   String get description {
     if (_description == null) _description = _thunk();
     return _description;
   }
 
   String toString() => description;
 
   PendingCallback._(this._thunk);
 }