Move implementation from IterableBase to Iterable.

sdk/lib/collection/splay_tree.dart

Index: sdk/lib/collection/splay_tree.dart
diff --git a/sdk/lib/collection/splay_tree.dart b/sdk/lib/collection/splay_tree.dart
index b9c1994381cff080258b10e0a4ae3805530c95ad..b5fcb93876f21b435abc91fb176380628a3b9863 100644
--- a/sdk/lib/collection/splay_tree.dart
+++ b/sdk/lib/collection/splay_tree.dart
@@ -599,8 +599,8 @@ abstract class _SplayTreeIterator<T> implements Iterator<T> {
   T _getValue(_SplayTreeNode node);
 }
 
-class _SplayTreeKeyIterable<K> extends IterableBase<K>
-                              implements EfficientLength {
+class _SplayTreeKeyIterable<K> extends Iterable<K>
+                               implements EfficientLength {
   _SplayTree<K> _tree;
   _SplayTreeKeyIterable(this._tree);
   int get length => _tree._count;
@@ -617,7 +617,7 @@ class _SplayTreeKeyIterable<K> extends IterableBase<K>
   }
 }
 
-class _SplayTreeValueIterable<K, V> extends IterableBase<V>
+class _SplayTreeValueIterable<K, V> extends Iterable<V>
                                     implements EfficientLength {
   SplayTreeMap<K, V> _map;
   _SplayTreeValueIterable(this._map);