Redo StreamTransformers so they work with Stack traces.

sdk/lib/_internal/pub/lib/src/utils.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.
 
 /// Generic utility functions. Stuff that should possibly be in core.
 library pub.utils;
 
 import 'dart:async';
 import "dart:collection";
 import "dart:convert";
@@ skipping 389 matching lines @@
 // fixed.
 /// Splits [text] on its line breaks in a Windows-line-break-friendly way.
 List<String> splitLines(String text) =>
   text.split("\n").map((line) => line.replaceFirst(_trailingCR, "")).toList();
 
 /// Converts a stream of arbitrarily chunked strings into a line-by-line stream.
 /// The lines don't include line termination characters. A single trailing
 /// newline is ignored.
 Stream<String> streamToLines(Stream<String> stream) {
   var buffer = new StringBuffer();
-  return stream.transform(new StreamTransformer(
+  return stream.transform(new StreamTransformer.fromHandlers(
       handleData: (chunk, sink) {
         var lines = splitLines(chunk);
         var leftover = lines.removeLast();
         for (var line in lines) {
           if (!buffer.isEmpty) {
             buffer.write(line);
             line = buffer.toString();
             buffer = new StringBuffer();
           }
 
@@ skipping 313 matching lines @@
     error is DirectoryException ||
     error is FileException ||
     error is HttpException ||
     error is HttpException ||
     error is LinkException ||
     error is OSError ||
     error is ProcessException ||
     error is SocketException ||
     error is WebSocketException;
 }