Add "last" setter to List.

sdk/lib/_internal/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 346 matching lines @@
     return JS('var', '#[#]', this, index);
   }
 
   void operator []=(int index, E value) {
     checkMutable('indexed set');
     if (index is !int) throw new ArgumentError(index);
     if (index >= length || index < 0) throw new RangeError.value(index);
     JS('void', r'#[#] = #', this, index, value);
   }
 
+  void set last(E value) {
+    checkMutable('indexed set');
+    if (length == 0) throw IterableElementError.noElement();
+    JS('void', r'#[#] = #', this, this.length - 1, value);
+  }
+
   Map<int, E> asMap() {
     return IterableMixinWorkaround.asMapList(this);
   }
 }
 
 /**
  * Dummy subclasses that allow the backend to track more precise
  * information about arrays through their type. The CPA type inference
  * relies on the fact that these classes do not override [] nor []=.
  */
 class JSMutableArray<E> extends JSArray<E> implements JSMutableIndexable {}
 class JSFixedArray<E> extends JSMutableArray<E> {}
 class JSExtendableArray<E> extends JSMutableArray<E> {}