dart2js: Change mirror flag message.

pkg/compiler/lib/src/warnings.dart

 // Copyright (c) 2011, 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 dart2js;
 
 const DONT_KNOW_HOW_TO_FIX = "Computer says no!";
 
 /**
  * The messages in this file should meet the following guide lines:
@@ skipping 2368 matching lines @@
 ****************************************************************
 * WARNING: dart:mirrors support in dart2js is experimental,
 *          and not recommended.
 *          This implementation of mirrors is incomplete,
 *          and often greatly increases the size of the generated
 *          JavaScript code.
 *
 * Your app imports dart:mirrors via:''''''
 $IMPORT_EXPERIMENTAL_MIRRORS_PADDING#{importChain}
 *
-* Starting with Dart 1.9, you must use the
-* --enable-experimental-mirrors command-line flag to opt-in.
-* You can begin using this flag now if mirrors support is critical.
+* You can disable this message by using the --enable-experimental-mirrors
+* command-line flag.
 *
 * To learn what to do next, please visit:
 *    http://dartlang.org/dart2js-reflection
 ****************************************************************
 ''');
 
   static const MessageKind CALL_NOT_SUPPORTED_ON_NATIVE_CLASS =
       const MessageKind(
           "Non-supported 'call' member on a native class, or a "
           "subclass of a native class.");
@@ skipping 53 matching lines @@
   static String convertToString(value) {
     if (value is ErrorToken) {
       // Shouldn't happen.
       return value.assertionMessage;
     } else if (value is Token) {
       value = value.value;
     }
     return '$value';
   }
 }