Remove private class helping the parser to construct literal lists and maps.

runtime/lib/array_patch.dart

Index: runtime/lib/array_patch.dart
===================================================================
--- runtime/lib/array_patch.dart	(revision 14872)
+++ runtime/lib/array_patch.dart	(working copy)
@@ -21,4 +21,15 @@
     }
     return list;
   }
+
+  // Factory constructing a mutable List from a parser generated List literal.
+  // [elements] contains elements that are already type checked.
+  factory List._fromLiteral(List elements) {
+    var list = new List<E>();
+    if (elements.length > 0) {
+      list._setData(elements);
+      list.length = elements.length;
+    }
+    return list;
+  }
 }