Base JavaScript code position computation on JavaScript tracer.

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 'source_information.dart';
 
@@ skipping 84 matching lines @@
   }
 
   void close() {
     if (isClosed) {
       throw new StateError("Code output is already closed.");
     }
     isClosed = true;
   }
 }
 
+abstract class BufferedCodeOutput {
+  String getText();
+}
+
 /// [CodeOutput] using a [StringBuffer] as backend.
-class CodeBuffer extends AbstractCodeOutput {
+class CodeBuffer extends AbstractCodeOutput implements BufferedCodeOutput {
   StringBuffer buffer = new StringBuffer();
 
   @override
   void _addInternal(String text) {
     buffer.write(text);
   }
 
   @override
   int get length => buffer.length;
 
@@ skipping 24 matching lines @@
   }
 
   void close() {
     output.close();
     super.close();
     if (_listeners != null) {
       _listeners.forEach((listener) => listener.onDone(length));
     }
   }
 }