support class native clause

pkg/analyzer/lib/src/dart/error/syntactic_errors.dart

 // Copyright (c) 2014, 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.
 
 /**
  * The errors produced during syntactic analysis (scanning and parsing).
  */
 library analyzer.src.dart.error.syntactic_errors;
 
 import 'package:analyzer/error/error.dart';
@@ skipping 726 matching lines @@
           "through native extensions.",
           "Try removing the native clause.");
 
   static const ParserErrorCode NATIVE_FUNCTION_BODY_IN_NON_SDK_CODE =
       const ParserErrorCode(
           'NATIVE_FUNCTION_BODY_IN_NON_SDK_CODE',
           "Native functions can only be declared in the SDK and code that is "
           "loaded through native extensions.",
           "Try removing the word 'native'.");
 
+  static const ParserErrorCode NATIVE_CLAUSE_SHOULD_BE_ANNOTATION =
+      const ParserErrorCode(
+          'NATIVE_CLAUSE_SHOULD_BE_ANNOTATION',
+          "Native clause in this form is deprecated.",
+          "Try removing this native clause and adding @native()"
+          " or @native('native-name') before the declaration.");
+
   static const ParserErrorCode NON_CONSTRUCTOR_FACTORY = const ParserErrorCode(
       'NON_CONSTRUCTOR_FACTORY',
       "Only a constructor can be declared to be a factory.",
       "Try removing the keyword 'factory'.");
 
   static const ParserErrorCode NON_IDENTIFIER_LIBRARY_NAME =
       const ParserErrorCode(
           'NON_IDENTIFIER_LIBRARY_NAME',
           "The name of a library must be an identifier.",
           "Try using an identifier as the name of the library.");
@@ skipping 233 matching lines @@
    */
   const ParserErrorCode(String name, String message, [String correction])
       : super(name, message, correction);
 
   @override
   ErrorSeverity get errorSeverity => ErrorSeverity.ERROR;
 
   @override
   ErrorType get type => ErrorType.SYNTACTIC_ERROR;
 }