Improve parser error recovery.

dart/sdk/lib/_internal/compiler/implementation/scanner/partial_parser.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 scanner;
 
 class PartialParser extends Parser {
   PartialParser(Listener listener) : super(listener);
 
   Token parseClassBody(Token token) => skipClassBody(token);
@@ skipping 14 matching lines @@
     }
   }
 
   Token skipExpression(Token token) {
     while (true) {
       final kind = token.kind;
       final value = token.stringValue;
       if ((identical(kind, EOF_TOKEN)) ||
           (identical(value, ';')) ||
           (identical(value, ',')) ||
+          (identical(value, '}')) ||
+          (identical(value, ')')) ||
           (identical(value, ']'))) {
         break;
       }
       if (identical(value, '=') ||
           identical(value, '?') ||
           identical(value, ':')) {
         var nextValue = token.next.stringValue;
         if (identical(nextValue, 'const')) {
           token = token.next;
           nextValue = token.next.stringValue;
@@ skipping 89 matching lines @@
         return token;
       }
       return listener.unexpected(token);
     }
     BeginGroupToken beginGroupToken = token;
     Token endToken = beginGroupToken.endGroup;
     listener.endFormalParameters(0, token, endToken);
     return endToken.next;
   }
 }