add support for native methods in class

pkg/compiler/lib/src/parser/element_listener.dart

 // Copyright (c) 2015, 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.
 
 library dart2js.parser.element_listener;
 
 import 'package:front_end/src/fasta/fasta_codes.dart' show Message;
 
 import 'package:front_end/src/fasta/fasta_codes.dart' as codes;
 
@@ skipping 509 matching lines @@
         message.code != codes.codeUnterminatedComment &&
         message.code != codes.codeUnterminatedString) {
       throw new ParserError.fromTokens(token, token, message);
     } else {
       return next;
     }
   }
 
   @override
   void handleRecoverableError(Token token, Message message) {
+    if (message == codes.messageNativeClauseShouldBeAnnotation) return;
     handleError(token, message);
   }
 
   @override
   void handleInvalidExpression(Token token) {
     pushNode(new ErrorExpression(token));
   }
 
   @override
   void handleInvalidFunctionBody(Token token) {
     lastErrorWasNativeFunctionBody = false;
   }
 
   @override
   void handleInvalidTypeReference(Token token) {
     pushNode(null);
   }
 
   Token handleError(Token token, Message message) {
     MessageKind errorCode;
     Map<String, dynamic> arguments = message.arguments;
 
     switch (message.code.dart2jsCode) {
       case "MISSING_TOKEN_BEFORE_THIS":
         String expected = arguments["string"];
-        // TODO(danrubel) This functionality is being replaced by
+        // TODO(danrubel): This functionality is being replaced by
         // the parser's ensureSemicolon method.
         if (identical(";", expected)) {
           // When a semicolon is missing, it often leads to an error on the
           // following line. So we try to find the token preceding the semicolon
           // and report that something is missing *after* it.
           Token preceding = findPrecedingToken(token);
           if (preceding == token) {
             reportErrorFromToken(token, MessageKind.MISSING_TOKEN_BEFORE_THIS,
                 {'token': expected});
           } else {
@@ skipping 387 matching lines @@
       memberErrors = memberErrors.tail.prepend(true);
     }
     reporter.reportErrorMessage(spannable, errorCode, arguments);
   }
 
   void reportErrorFromToken(Token token, MessageKind errorCode,
       [Map arguments = const {}]) {
     reportError(reporter.spanFromToken(token), errorCode, arguments);
   }
 }