Recommit changing List.skip/take/revert returns Iterable and remove mappedBy.

tests/lib/async/stream_controller_async_test.dart

Index: tests/lib/async/stream_controller_async_test.dart
diff --git a/tests/lib/async/stream_controller_async_test.dart b/tests/lib/async/stream_controller_async_test.dart
index 79b85682be7d1174a10c1eef0253b95fa49dc875..36278bded8e7d7c2a871fe64e54e1ce286d5d4a3 100644
--- a/tests/lib/async/stream_controller_async_test.dart
+++ b/tests/lib/async/stream_controller_async_test.dart
@@ -439,7 +439,7 @@ testRethrow() {
   }
 
   testStream("where", (s, act) => s.where(act));
-  testStream("mappedBy", (s, act) => s.map(act));
+  testStream("map", (s, act) => s.map(act));
   testStream("expand", (s, act) => s.expand(act));
   testStream("where", (s, act) => s.where(act));
   testStreamError("handleError", (s, act) => s.handleError(act));