Merge kernel closure conversion into the Dart SDK

pkg/kernel/test/round_trip.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.round_trip;
 
 import 'dart:async';
 import 'dart:io';
 import 'package:kernel/binary/ast_from_binary.dart';
 import 'package:kernel/binary/ast_to_binary.dart';
 import 'package:kernel/binary/loader.dart';
@@ skipping 35 matching lines @@
 /// trace shows what the serializer was doing when the output started to differ.
 class BinaryPrinterWithExpectedOutput extends BinaryPrinter {
   final List<int> expectedBytes;
   int offset = 0;
 
   static const int eof = -1;
 
   BinaryPrinterWithExpectedOutput(this.expectedBytes)
       : super(new IOSink(new DummyStreamConsumer()));
 
-
   String show(int byte) {
     if (byte == eof) return 'EOF';
     return '$byte (0x${byte.toRadixString(16).padLeft(2, "0")})';
   }
 
   @override
   void writeByte(int byte) {
     if (offset == expectedBytes.length || expectedBytes[offset] != byte) {
       int expected =
           (offset >= expectedBytes.length) ? eof : expectedBytes[offset];
       throw 'At offset $offset: '
           'Expected ${show(expected)} but found ${show(byte)}';
     }
     ++offset;
   }
 
   @override
   void writeBytes(List<int> bytes) {
     bytes.forEach(writeByte);
   }
 }