Remove Collection, Collections and clean up List/Set/Queue implementations of retain/remove.

sdk/lib/collection/list.dart

Index: sdk/lib/collection/list.dart
diff --git a/sdk/lib/collection/list.dart b/sdk/lib/collection/list.dart
index 6231c190ef11301ce7585b6f617d8556b634a3a4..354e59edae919874b110ec34348e3a01d5d111c9 100644
--- a/sdk/lib/collection/list.dart
+++ b/sdk/lib/collection/list.dart
@@ -249,21 +249,6 @@ abstract class ListMixin<E> implements List<E> {
     }
   }
 
-  void removeAll(Iterable<Object> elements) {
-    if (elements is! Set) {
-      elements = elements.toSet();
-    }
-    _filter(this, elements.contains, false);
-  }
-
-
-  void retainAll(Iterable<E> elements) {
-    if (elements is! Set) {
-      elements = elements.toSet();
-    }
-    _filter(this, elements.contains, true);
-  }
-
   void removeWhere(bool test(E element)) {
     _filter(this, test, false);
   }