Add fromIterable(s) constructors in SplayTreeMap and LinkedHashMap.

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 84e61e10d4386e01a8e85514a643374b22ad59d9..a5e19b2ef4a02f31809a5af34444dd68ce43c756 100644
--- a/sdk/lib/collection/splay_tree.dart
+++ b/sdk/lib/collection/splay_tree.dart
@@ -251,6 +251,20 @@ class SplayTreeMap<K, V> extends _SplayTree<K> implements Map<K, V> {
   factory SplayTreeMap.from(Map<K, V> other, [int compare(K key1, K key2)]) =>
       new SplayTreeMap(compare)..addAll(other);
 
+  factory SplayTreeMap.fromIterable(Iterable iterable,
+      {K key(element), V value(element), int compare(K key1, K key2)}) {
+    SplayTreeMap<K, V> map = new SplayTreeMap<K, V>(compare);
+    Maps._fillMapWithMappedIterable(map, iterable, key: key, value: value);
+    return map;
+  }
+
+  factory SplayTreeMap.fromIterables(Iterable<K> keys, Iterable<V> values,
+      [int compare(K key1, K key2)]) {
+    SplayTreeMap<K, V> map = new SplayTreeMap<K, V>(compare);
+    Maps._fillMapWithIterables(map, keys, values);
+    return map;
+  }
+
   int _compare(K key1, K key2) => _comparator(key1, key2);
 
   SplayTreeMap._internal();