Big merge from experimental to bleeding edge.

pkg/serialization/lib/src/serialization_helpers.dart

Index: pkg/serialization/lib/src/serialization_helpers.dart
diff --git a/pkg/serialization/lib/src/serialization_helpers.dart b/pkg/serialization/lib/src/serialization_helpers.dart
index 335bc0d475297ba09bd3af5e05b55c6cba057237..407c6562d2b765f6c5c5553e9f6e371672b3196b 100644
--- a/pkg/serialization/lib/src/serialization_helpers.dart
+++ b/pkg/serialization/lib/src/serialization_helpers.dart
@@ -18,7 +18,7 @@ doNothing(x) => x;
 
 /** Concatenate two lists. Handle the case where one or both might be null. */
 // TODO(alanknight): Remove once issue 5342 is resolved.
-List append(List a, List b) {
+List append(Iterable a, Iterable b) {
   if (a == null) {
     return (b == null) ? [] : new List.from(b);
   }
@@ -29,11 +29,11 @@ List append(List a, List b) {
 }
 
 /**
- * Return a sorted version of [aCollection], using the default sort criterion.
- * Always returns a List, regardless of the type of [aCollection].
+ * Return a sorted version of [anIterable], using the default sort criterion.
+ * Always returns a List, regardless of the type of [anIterable].
  */
-List sorted(aCollection) {
-  var result = new List.from(aCollection);
+List sorted(anIterable) {
+  var result = new List.from(anIterable);
   result.sort();
   return result;
 }
@@ -105,9 +105,10 @@ class MapLikeIterableForList extends MapLikeIterable {
   MapLikeIterableForList(collection) : super(collection);
 
   void forEach(f) {
-    Iterator iterator = collection.iterator();
+    Iterator iterator = collection.iterator;
     for (var i = 0; i < collection.length; i++) {
-      f(i, iterator.next());
+      iterator.moveNext();
+      f(i, iterator.current);
     }
   }
 
@@ -129,6 +130,13 @@ values(x) {
   throw new ArgumentError("Invalid argument");
 }
 
+mapValues(x, f) {
+  if (x is Set) return x.mappedBy(f).toSet();
+  if (x is Iterable) return x.mappedBy(f).toList();
+  if (x is Map) return new ListLikeIterable(x).map(f);
+  throw new ArgumentError("Invalid argument");
+}
+
 /**
  * A class for iterating over things as if they were Lists, which primarily
  * means that forEach passes one argument, and map() returns a new Map
@@ -159,7 +167,7 @@ class ListLikeIterable {
   /**
    * Return an iterator that behaves like a List iterator, taking one parameter.
    */
-  Iterator iterator() => collection.values.iterator();
+  Iterator get iterator => collection.values.iterator;
 }
 
 /**