Get rid of Chain.track in pub.

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

Index: sdk/lib/_internal/pub/lib/src/command/uploader.dart
diff --git a/sdk/lib/_internal/pub/lib/src/command/uploader.dart b/sdk/lib/_internal/pub/lib/src/command/uploader.dart
index 0324dcbb92127171674a1299eca65c58cc995772..f74915d9379f62eb96c054babeafda253d5d2f47 100644
--- a/sdk/lib/_internal/pub/lib/src/command/uploader.dart
+++ b/sdk/lib/_internal/pub/lib/src/command/uploader.dart
@@ -16,7 +16,6 @@ import '../io.dart';
 import '../log.dart' as log;
 import '../oauth2.dart' as oauth2;
 import '../source/hosted.dart';
-import '../utils.dart';
 
 /// Handles the `uploader` pub command.
 class UploaderCommand extends PubCommand {
@@ -58,7 +57,7 @@ class UploaderCommand extends PubCommand {
       return flushThenExit(exit_codes.USAGE);
     }
 
-    return syncFuture(() {
+    return new Future.sync(() {
       var package = commandOptions['package'];
       if (package != null) return package;
       return new Entrypoint(path.current, cache).root.name;