Remove deprecated parts of dart:async.

pkg/barback/lib/src/build_result.dart

Index: pkg/barback/lib/src/build_result.dart
diff --git a/pkg/barback/lib/src/build_result.dart b/pkg/barback/lib/src/build_result.dart
index 65e82690ccc9f9ea23015fc44b745b61b650db47..34a4c0a6e574a44120dc2bbdaa38e542cc23f5b8 100644
--- a/pkg/barback/lib/src/build_result.dart
+++ b/pkg/barback/lib/src/build_result.dart
@@ -47,7 +47,8 @@ class BuildResult {
     if (succeeded) return "success";
 
     return "errors:\n" + errors.map((error) {
-      var stackTrace = getAttachedStackTrace(error);
+      var stackTrace = null;
+      if (error is Error) stackTrace = error.stackTrace;

[Bob Nystrom, 2013/10/30 15:56:34]

error will always be an instance of BarbackException, so you can rely on it
having a stackTrace property, (and the is check here will always fail). You
should be able to just do:

var stackTrace = new Trace.from(error.stackTrace);

[floitsch, 2013/10/30 18:39:40]

Done.

       if (stackTrace != null) stackTrace = new Trace.from(stackTrace);
 
       var msg = new StringBuffer();