Make getKeys, getValues getters (keys, values).

lib/coreimpl/splay_tree.dart

Index: lib/coreimpl/splay_tree.dart
diff --git a/lib/coreimpl/splay_tree.dart b/lib/coreimpl/splay_tree.dart
index 49a28e5be18da8d86f037156feeaeef70e606b4e..974c2bcb78cbb28f0c3fd015ae3645cd26a525f8 100644
--- a/lib/coreimpl/splay_tree.dart
+++ b/lib/coreimpl/splay_tree.dart
@@ -222,13 +222,13 @@ class SplayTreeMap<K extends Comparable, V> implements Map<K, V> {
     return visit(_root);
   }
 
-  Collection<K> getKeys() {
+  Collection<K> get keys {
     List<K> list = new List<K>();
     forEach((K k, V v) { list.add(k); });
     return list;
   }
 
-  Collection<V> getValues() {
+  Collection<V> get values {
     List<V> list = new List<V>();
     forEach((K k, V v) { list.add(v); });
     return list;