Add internal operation that converts a growable list to a fixed list.

runtime/lib/growable_array.cc

 // 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.
 
 #include "platform/assert.h"
 
 #include "vm/assembler.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/exceptions.h"
 #include "vm/native_entry.h"
@@ skipping 73 matching lines @@
 
 DEFINE_NATIVE_ENTRY(GrowableList_setData, 2) {
   const GrowableObjectArray& array =
       GrowableObjectArray::CheckedHandle(arguments->NativeArgAt(0));
   GET_NON_NULL_NATIVE_ARGUMENT(Array, data, arguments->NativeArgAt(1));
   ASSERT(data.Length() > 0);
   array.SetData(data);
   return Object::null();
 }
 
+
+DEFINE_NATIVE_ENTRY(Internal_makeListFixedLength, 1) {
+  GET_NON_NULL_NATIVE_ARGUMENT(GrowableObjectArray, array,
+                               arguments->NativeArgAt(0));
+  return Array::MakeArray(array);
+}
+
 }  // namespace dart