Remove _BufferList from dart:io and now use BytesBuilder.

sdk/lib/io/file_impl.dart

 // Copyright (c) 2013, 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.
 
 part of dart.io;
 
 // Read the file in blocks of size 64k.
 const int _BLOCK_SIZE = 64 * 1024;
 
 
@@ skipping 461 matching lines @@
       throw new ArgumentError(
           "Wrong FileMode. Use FileMode.WRITE or FileMode.APPEND");
     }
     var consumer = new _FileStreamConsumer(this, mode);
     return new IOSink(consumer, encoding: encoding);
   }
 
   Future<List<int>> readAsBytes() {
     _ensureFileService();
     Completer<List<int>> completer = new Completer<List<int>>();
-    var chunks = new _BufferList();
+    var builder = new BytesBuilder();
     openRead().listen(
-      (d) => chunks.add(d),
+      (d) => builder.add(d),
       onDone: () {
-        var result = chunks.readBytes();
-        completer.complete(result);
+        completer.complete(builder.takeBytes());
       },
       onError: (e) {
         completer.completeError(e);
       },
       cancelOnError: true);
     return completer.future;
   }
 
   List<int> readAsBytesSync() {
     var opened = openSync();
-    var chunks = new _BufferList();
+    var builder = new BytesBuilder();
     var data;
     while ((data = opened.readSync(_BLOCK_SIZE)).length > 0) {
-      chunks.add(data);
+      builder.add(data);
     }
     opened.closeSync();
-    return chunks.readBytes();
+    return builder.takeBytes();
   }
 
   Future<String> readAsString({Encoding encoding: Encoding.UTF_8}) {
     _ensureFileService();
     return readAsBytes().then((bytes) {
       return _decodeString(bytes, encoding);
     });
   }
 
   String readAsStringSync({Encoding encoding: Encoding.UTF_8}) {
@@ skipping 472 matching lines @@
 
   Future _closedException() {
     return new Future.error(new FileException("File closed", _path));
   }
 
   final String _path;
   int _id;
 
   SendPort _fileService;
 }