Make EfficientLength public, as EfficientLengthIterable.

sdk/lib/collection/list.dart

 // Copyright (c) 2013, 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.
 
 part of dart.collection;
 
 /**
  * Abstract implementation of a list.
  *
  * `ListBase` can be used as a base class for implementing the `List` interface.
@@ skipping 371 matching lines @@
       }
     } else {
       for (int i = 0; i < length; i++) {
         this[start + i] = otherList[otherStart + i];
       }
     }
   }
 
   void replaceRange(int start, int end, Iterable<E> newContents) {
     RangeError.checkValidRange(start, end, this.length);
-    if (newContents is! EfficientLength) {
+    if (newContents is! EfficientLengthIterable) {
       newContents = newContents.toList();
     }
     int removeLength = end - start;
     int insertLength = newContents.length;
     if (removeLength >= insertLength) {
       int delta = removeLength - insertLength;
       int insertEnd = start + insertLength;
       int newLength = this.length - delta;
       this.setRange(start, insertEnd, newContents);
       if (delta != 0) {
@@ skipping 66 matching lines @@
 
   E removeAt(int index) {
     E result = this[index];
     setRange(index, this.length - 1, this, index + 1);
     length--;
     return result;
   }
 
   void insertAll(int index, Iterable<E> iterable) {
     RangeError.checkValueInInterval(index, 0, length, "index");
-    if (iterable is EfficientLength) {
+    if (iterable is EfficientLengthIterable) {
       iterable = iterable.toList();
     }
     int insertionLength = iterable.length;
     // There might be errors after the length change, in which case the list
     // will end up being modified but the operation not complete. Unless we
     // always go through a "toList" we can't really avoid that.
     this.length += insertionLength;
     setRange(index + insertionLength, this.length, this, index);
     setAll(index, iterable);
   }
 
   void setAll(int index, Iterable<E> iterable) {
     if (iterable is List) {
       setRange(index, index + iterable.length, iterable);
     } else {
       for (E element in iterable) {
         this[index++] = element;
       }
     }
   }
 
   Iterable<E> get reversed => new ReversedListIterable<E>(this);
 
   String toString() => IterableBase.iterableToFullString(this, '[', ']');
 }