Clean up some warnings and deprecated calls.

utils/tests/pub/version_solver_test.dart

Index: utils/tests/pub/version_solver_test.dart
diff --git a/utils/tests/pub/version_solver_test.dart b/utils/tests/pub/version_solver_test.dart
index eb37f640d893097449827f1a9fd546d3d2f9777f..3d4b020e2cb07d504ca977f22d10015be2aed937 100644
--- a/utils/tests/pub/version_solver_test.dart
+++ b/utils/tests/pub/version_solver_test.dart
@@ -465,11 +465,11 @@ class MockSource extends Source {
       : _packages = <String, Map<Version, Package>>{};
 
   Future<List<Version>> getVersions(String name, String description) {
-    return fakeAsync(() => _packages[description].keys.toList());
+    return defer(() => _packages[description].keys.toList());
   }
 
   Future<Pubspec> describe(PackageId id) {
-    return fakeAsync(() {
+    return defer(() {
       return _packages[id.name][id.version].pubspec;
     });
   }
@@ -526,15 +526,6 @@ class MockVersionlessSource extends Source {
   }
 }
 
-Future fakeAsync(callback()) {
-  var completer = new Completer();
-  Timer.run(() {
-    completer.complete(callback());
-  });
-
-  return completer.future;
-}
-
 Pair<String, Source> parseSource(String name) {
   var match = new RegExp(r"(.*) from (.*)").firstMatch(name);
   if (match == null) return new Pair<String, Source>(name, source1);