Implement initializer asserts.

pkg/front_end/lib/src/fasta/source/outline_builder.dart

 // Copyright (c) 2016, 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.outline_builder;
 
 import 'package:kernel/ast.dart' show ProcedureKind;
 
 import '../fasta_codes.dart' show FastaMessage, codeExpectedBlockToSkip;
 
@@ skipping 132 matching lines @@
     String uri = pop();
     List<MetadataBuilder> metadata = pop();
     if (uri != null) {
       library.addImport(metadata, uri, conditionalUris, prefix, combinators,
           deferredKeyword != null, importKeyword.charOffset, prefixOffset);
     }
     checkEmpty(importKeyword.charOffset);
   }
 
   @override
-  void handleRecoverExpression(Token token) {
+  void handleRecoverExpression(Token token, FastaMessage message) {
     debugEvent("RecoverExpression");
     push(NullValue.Expression);
     push(token.charOffset);
   }
 
   @override
   void endPart(Token partKeyword, Token semicolon) {
     debugEvent("Part");
     int charOffset = popCharOffset();
     String uri = pop();
@@ skipping 646 matching lines @@
   Link<Token> handleMemberName(Link<Token> identifiers) {
     if (!enableNative || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers);
   }
 
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }