Make EfficientLength public, as EfficientLengthIterable.

sdk/lib/_internal/compiler/js_lib/js_array.dart

 // Copyright (c) 2012, 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 _interceptors;
 
 /**
  * The interceptor class for [List]. The compiler recognizes this
  * class as an interceptor, and changes references to [:this:] to
  * actually use the receiver of the method, which is generated as an extra
@@ skipping 107 matching lines @@
     if (index is !int) throw new ArgumentError(index);
     if (index < 0 || index > length) {
       throw new RangeError.value(index);
     }
     JS('void', r'#.splice(#, 0, #)', this, index, value);
   }
 
   void insertAll(int index, Iterable<E> iterable) {
     checkGrowable('insertAll');
     RangeError.checkValueInInterval(index, 0, this.length, "index");
-    if (iterable is! EfficientLength) {
+    if (iterable is! EfficientLengthIterable) {
       iterable = iterable.toList();
     }
     int insertionLength = iterable.length;
     this.length += insertionLength;
     int end = index + insertionLength;
     this.setRange(end, this.length, this, index);
     this.setRange(index, end, iterable);
   }
 
   void setAll(int index, Iterable<E> iterable) {
@@ skipping 294 matching lines @@
     RangeError.checkValidRange(start, end, this.length);
     for (int i = start; i < end; i++) {
       // Store is safe since [fillValue] type has been checked as parameter.
       JS('', '#[#] = #', this, i, fillValue);
     }
   }
 
   void replaceRange(int start, int end, Iterable<E> replacement) {
     checkGrowable('replace range');
     RangeError.checkValidRange(start, end, this.length);
-    if (replacement is! EfficientLength) {
+    if (replacement is! EfficientLengthIterable) {
       replacement = replacement.toList();
     }
     int removeLength = end - start;
     int insertLength = replacement.length;
     if (removeLength >= insertLength) {
       int delta = removeLength - insertLength;
       int insertEnd = start + insertLength;
       int newLength = this.length - delta;
       this.setRange(start, insertEnd, replacement);
       if (delta != 0) {
@@ skipping 186 matching lines @@
 
     if (_index >= length) {
       _current = null;
       return false;
     }
     _current = _iterable[_index];
     _index++;
     return true;
   }
 }