Moving ListBase, FixedLengthListMixin and UmodifiableListMixin to collection.

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 1e40785f3a6540ab555979cb6cf7ba87fe7236d6..d8b85833e8974c8d94754795f388bf4e625d4bfe 100644
--- a/sdk/lib/_collection_dev/list.dart
+++ b/sdk/lib/_collection_dev/list.dart
@@ -619,44 +619,6 @@ abstract class UnmodifiableListMixin<E> {
   }
 }
 
-
-/**
- * Abstract implementation of a list.
- *
- * All operations are defined in terms of `length`, `operator[]`,
- * `operator[]=` and `length=`, which need to be implemented.
- */
-abstract class ListBase<E> extends ListMixin<E> implements List<E> {}
-
-/**
- * Abstract implementation of a fixed-length list.
- *
- * All operations are defined in terms of `length`, `operator[]` and
- * `operator[]=`, which need to be implemented.
- */
-abstract class FixedLengthListBase<E> extends ListBase<E>
-                                      with FixedLengthListMixin<E> {}
-
-/**
- * Abstract implementation of an unmodifiable list.
- *
- * All operations are defined in terms of `length` and `operator[]`,
- * which need to be implemented.
- */
-abstract class UnmodifiableListBase<E> extends ListBase<E>
-                                       with UnmodifiableListMixin<E> {}
-
-/** An empty fixed-length (and therefore unmodifiable) list. */
-class EmptyList<E> extends FixedLengthListBase<E> {
-  int get length => 0;
-  E operator[](int index) { throw new RangeError.value(index); }
-  void operator []=(int index, E value) { throw new RangeError.value(index); }
-  Iterable<E> skip(int count) => const EmptyIterable();
-  Iterable<E> take(int count) => const EmptyIterable();
-  Iterable<E> get reversed => const EmptyIterable();
-  void sort([int compare(E a, E b)]) {}
-}
-
 class ReversedListIterable<E> extends ListIterable<E> {
   Iterable<E> _source;
   ReversedListIterable(this._source);
@@ -669,7 +631,7 @@ class ReversedListIterable<E> extends ListIterable<E> {
 /**
  * An [Iterable] of the UTF-16 code units of a [String] in index order.
  */
-class CodeUnits extends UnmodifiableListBase<int> {
+class CodeUnits extends ListMixin<int> with UnmodifiableListMixin<int> {
   /** The string that this is the code units of. */
   String _string;