Remove last vestiges of removeAll from typed lists.

sdk/lib/_collection_dev/list.dart

Index: sdk/lib/_collection_dev/list.dart
diff --git a/sdk/lib/_collection_dev/list.dart b/sdk/lib/_collection_dev/list.dart
index 971f7ad2da06cbe677cfa87ff893b5827841ee8b..3266d6c0e713998a9a2a2da6ccb94d8117a995c8 100644
--- a/sdk/lib/_collection_dev/list.dart
+++ b/sdk/lib/_collection_dev/list.dart
@@ -125,16 +125,6 @@ abstract class UnmodifiableListMixin<E> {
         "Cannot remove from an unmodifiable list");
   }
 
-  void removeAll(Iterable elements) {
-    throw new UnsupportedError(
-        "Cannot remove from an unmodifiable list");
-  }
-
-  void retainAll(Iterable elements) {
-    throw new UnsupportedError(
-        "Cannot remove from an unmodifiable list");
-  }
-
   void removeWhere(bool test(E element)) {
     throw new UnsupportedError(
         "Cannot remove from an unmodifiable list");