Make Iterable more powerful (and lazy).

sdk/lib/core/list.dart

Index: sdk/lib/core/list.dart
diff --git a/sdk/lib/core/list.dart b/sdk/lib/core/list.dart
index b4948a3c1680aa616a39f6b605ea2363296015cb..9addc6d915803d4a6aa01ec99b94a87a543d95db 100644
--- a/sdk/lib/core/list.dart
+++ b/sdk/lib/core/list.dart
@@ -52,9 +52,7 @@ interface List<E> extends Collection<E>, Sequence<E>
   void add(E value);
 
   /**
-   * Adds [value] at the end of the list, extending the length by
-   * one. Throws an [UnsupportedError] if the list is not
-   * extendable.
+   * Alias for [add].
    */
   void addLast(E value);
 
@@ -129,6 +127,13 @@ interface List<E> extends Collection<E>, Sequence<E>
   E get last;
 
   /**
+   * Returns a read-only view of [this].
+   *
+   * The returned [List] is backed by [this] but cannot change [this].
+   */
+  List<E> get view;
+
+  /**
    * Returns a new list containing [length] elements from the list,
    * starting at  [start].
    * Returns an empty list if [length] is 0.