Refactor CompilerOutput

pkg/compiler/lib/src/io/code_output.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 dart2js.code_output;
 
-import 'dart:async';
-
+import '../../compiler_new.dart';
 import 'source_information.dart';
 
 /// Listener interface for [CodeOutput] activity.
 abstract class CodeOutputListener {
   /// Called when [text] is added to the output.
   void onText(String text);
 
   /// Called when the output is closed with a final length of [length].
   void onDone(int length);
 }
@@ skipping 104 matching lines @@
   }
 
   String toString() {
     throw "Don't use CodeBuffer.toString() since it drops sourcemap data.";
   }
 }
 
 /// [CodeOutput] using a [CompilationOutput] as backend.
 class StreamCodeOutput extends AbstractCodeOutput {
   int length = 0;
-  final EventSink<String> output;
+  final OutputSink output;
   final List<CodeOutputListener> _listeners;
 
   StreamCodeOutput(this.output, [this._listeners]);
 
   @override
   void _addInternal(String text) {
     output.add(text);
     length += text.length;
     if (_listeners != null) {
       _listeners.forEach((listener) => listener.onText(text));
     }
   }
 
   void close() {
     output.close();
     super.close();
     if (_listeners != null) {
       _listeners.forEach((listener) => listener.onDone(length));
     }
   }
 }