Resynthesize constructor initializers from Kernel.

pkg/kernel/lib/binary/ast_to_binary.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 kernel.ast_to_binary;
 
 import '../ast.dart';
 import '../import_table.dart';
 import 'tag.dart';
 import 'dart:convert';
 import 'dart:typed_data';
@@ skipping 457 matching lines @@
     writeName(node.name);
     writeUriReference(node.fileUri ?? '');
     writeAnnotationList(node.annotations);
     writeNode(node.type);
     writeOptionalNode(node.initializer);
     _variableIndexer = null;
   }
 
   visitInvalidInitializer(InvalidInitializer node) {
     writeByte(Tag.InvalidInitializer);
+    writeByte(node.isSynthetic ? 1 : 0);
   }
 
   visitFieldInitializer(FieldInitializer node) {
     writeByte(Tag.FieldInitializer);
+    writeByte(node.isSynthetic ? 1 : 0);
     writeReference(node.fieldReference);
     writeNode(node.value);
   }
 
   visitSuperInitializer(SuperInitializer node) {
     writeByte(Tag.SuperInitializer);
+    writeByte(node.isSynthetic ? 1 : 0);
     writeReference(node.targetReference);
     writeNode(node.arguments);
   }
 
   visitRedirectingInitializer(RedirectingInitializer node) {
     writeByte(Tag.RedirectingInitializer);
+    writeByte(node.isSynthetic ? 1 : 0);
     writeReference(node.targetReference);
     writeNode(node.arguments);
   }
 
   visitLocalInitializer(LocalInitializer node) {
     writeByte(Tag.LocalInitializer);
+    writeByte(node.isSynthetic ? 1 : 0);
     writeVariableDeclaration(node.variable);
   }
 
   visitFunctionNode(FunctionNode node) {
     writeByte(Tag.FunctionNode);
     assert(_variableIndexer != null);
     _variableIndexer.pushScope();
     var oldLabels = _labelIndexer;
     _labelIndexer = new LabelIndexer();
     var oldCases = _switchCaseIndexer;
@@ skipping 999 matching lines @@
     _sink.add(_buffer.sublist(0, length));
     _buffer = new Uint8List(SIZE);
     flushedLength += length;
     length = 0;
   }
 
   void flushAndDestroy() {
     _sink.add(_buffer.sublist(0, length));
   }
 }