Make EfficientLength extend Iterable.

tests/corelib/growable_list_test.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Sanity check on the growing behavior of a growable list.
 
 import "package:expect/expect.dart";
 
 void main() {
   testConstructor();
@@ skipping 16 matching lines @@
                    this.callbackIndex, this.callback);
   Iterator<int> get iterator => new CallbackIterator(this);
 }
 
 class TestIterable extends TestIterableBase {
   TestIterable(count, [callbackIndex = -1, callback])
       : super(-1, count, callbackIndex, callback);
   int get length => throw "SHOULD NOT BE CALLED";
 }
 
-// Implement Set for private EfficientLength interface.
+// Implement Set for private EfficientLengthIterable interface.
 class EfficientTestIterable extends TestIterableBase
                             implements Set<int> {
   EfficientTestIterable(length, count, [callbackIndex = -1, callback])
       : super(length, count, callbackIndex, callback);
   // Avoid warnings because we don't actually implement Set.
   noSuchMethod(i) => super.noSuchMethod(i);
 }
 
 class CallbackIterator implements Iterator<int> {
   TestIterableBase _iterable;
@@ skipping 49 matching lines @@
   Expect.throws(() => new List<int>(0x1000000000000000000000000000000),
                 (e) => e is ArgumentError, "bignum");
   Expect.throws(() => new List<int>(null), (e) => e is ArgumentError, "null");
   testThrowsOrTypeError(() => new List([] as Object),  // Cast to avoid warning.
                         (e) => e is ArgumentError, 'list');
   testThrowsOrTypeError(() => new List([42] as Object),
                         (e) => e is ArgumentError, "list2");
 }
 
 void testConcurrentModification() {
-  // Without EfficientLength interface
+  // Without EfficientLengthIterable interface
   {
     // Change length of list after 200 additions.
     var l = [];
     var ci = new TestIterable(257, 200, () {
       l.add("X");
     });
     Expect.throws(() {
       l.addAll(ci);
     }, (e) => e is ConcurrentModificationError, "cm1");
   }
 
   {
     // Change length of list after 200 additions.
     var l = [];
     var ci = new TestIterable(257, 200, () {
       l.length = 0;
     });
     Expect.throws(() {
       l.addAll(ci);
     }, (e) => e is ConcurrentModificationError, "cm2");
   }
 
-  // With EfficientLength interface (uses length).
+  // With EfficientLengthIterable interface (uses length).
   {
     // Change length of list after 20 additions.
     var l = [];
     var ci = new EfficientTestIterable(257, 257, 20, () {
       l.add("X");
     });
     Expect.throws(() {
       l.addAll(ci);
     }, (e) => e is ConcurrentModificationError, "cm3");
   }
@@ skipping 32 matching lines @@
   }
 
   {
     // Adding to yourself.
     var l = [1, 2, 3];
     Expect.throws(() { l.addAll(l); },
                   (e) => e is ConcurrentModificationError, "cm8");
   }
 }