new handleInvalidTopLevelDeclaration event in fasta parser

pkg/front_end/lib/src/fasta/parser/parser.dart

 // 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.
 
 library fasta.parser.parser;
 
 import '../fasta_codes.dart' show Code, Message, Template;
 
 import '../fasta_codes.dart' as fasta;
 
@@ skipping 243 matching lines @@
         (token.next.isIdentifier || optional("void", token.next))) {
       return parseTypedef(token);
     } else if (identical(value, 'library')) {
       return parseLibraryName(token);
     } else if (identical(value, 'import')) {
       return parseImport(token);
     } else if (identical(value, 'export')) {
       return parseExport(token);
     } else if (identical(value, 'part')) {
       return parsePartOrPartOf(token);
+    } else if (token.type == TokenType.IDENTIFIER || token.keyword != null) {
+      return parseTopLevelMember(token);
     } else {
-      return parseTopLevelMember(token);
+      reportRecoverableErrorWithToken(token, fasta.templateExpectedDeclaration);
+      listener.handleInvalidTopLevelDeclaration(token);
+      return token.next;
     }
   }
 
   /// library qualified ';'
   Token parseLibraryName(Token token) {
     Token libraryKeyword = token;
     listener.beginLibraryName(libraryKeyword);
     assert(optional('library', token));
     token = parseQualified(token.next, IdentifierContext.libraryName,
         IdentifierContext.libraryNameContinuation);
@@ skipping 3785 matching lines @@
   }
 
   Token reportUnexpectedToken(Token token) {
     return reportUnrecoverableErrorWithToken(
         token, fasta.templateUnexpectedToken);
   }
 }
 
 // TODO(ahe): Remove when analyzer supports generalized function syntax.
 typedef _MessageWithArgument<T> = Message Function(T);