Remove deprecated parts of dart:async.

sdk/lib/_internal/pub/lib/src/command.dart

Index: sdk/lib/_internal/pub/lib/src/command.dart
diff --git a/sdk/lib/_internal/pub/lib/src/command.dart b/sdk/lib/_internal/pub/lib/src/command.dart
index e8b7ed0e09fa14a9589802d0ed8de194b61dd5bc..2b8895eb49a073c3aa7bf40156e65385abcc8433 100644
--- a/sdk/lib/_internal/pub/lib/src/command.dart
+++ b/sdk/lib/_internal/pub/lib/src/command.dart
@@ -88,9 +88,7 @@ abstract class PubCommand {
 
     cache = new SystemCache.withSources(cacheDir, isOffline: isOffline);
 
-    handleError(error) {
-      var trace = getAttachedStackTrace(error);
-
+    handleError(error, trace) {
       // This is basically the top-level exception handler so that we don't
       // spew a stack trace on our users.
       var message;