Merge pull request dart-lang/package_config#94 from srawlins/unused-async

Remove unused dart:async imports.

pkgs/package_config/test/legacy/discovery_analysis_test.dart

diff --git a/pkgs/package_config/test/legacy/discovery_analysis_test.dart b/pkgs/package_config/test/legacy/discovery_analysis_test.dart
index 4be636d..7554d85 100644
--- a/pkgs/package_config/test/legacy/discovery_analysis_test.dart
+++ b/pkgs/package_config/test/legacy/discovery_analysis_test.dart
@@ -6,7 +6,6 @@
 @TestOn('vm')
 library package_config.discovery_analysis_test;
 
-import "dart:async";
 import "dart:io";
 
 import "package:package_config/discovery_analysis.dart";