Remove Encoding-enum from dart:io and add interface in dart:convert.

utils/testrunner/pipeline_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.
 
 part of pipeline;
 
 List log;
 var replyPort;
 int _procId = 1;
 Map _procs = {};
@@ skipping 83 matching lines @@
         stderr.add("Error starting process:");
         stderr.add("  Command: $command");
         stderr.add("  Error: ${e.toString()}");
         return new Future.value(-1);
       });
 }
 
 Future _pipeStream(Stream stream, List<String> destination,
                  Function outputMonitor) {
   return stream
-    .transform(new StringDecoder())
+    .transform(UTF8.decoder)
     .transform(new LineTransformer())
     .listen((String line) {
       if (config["immediate"] && line.startsWith('###')) {
         print(line.substring(3));
       }
       if (outputMonitor != null) {
         outputMonitor(line);
       }
       destination.add(line);
     })
@@ skipping 88 matching lines @@
 
 void completePipeline(List stdout, List stderr, [exitCode = 0]) {
   replyPort.send([stdout, stderr, log, exitCode]);
 }
 
 /** Utility function to log diagnostic messages. */
 void logMessage(msg) => log.add(msg);
 
 /** Turn file paths into standard form with forward slashes. */
 String normalizePath(String p) => (new Path(p)).toString();