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

pkg/analyzer_experimental/bin/analyzer.dart

 #!/usr/bin/env 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.
 
 /** The entry point for the analyzer. */
 library analyzer;
 
 import 'dart:async';
@@ skipping 62 matching lines @@
    */
   static ErrorSeverity runAsBatch(List<String> sharedArgs, BatchRunnerHandler handler) {
     stdout.writeln('>>> BATCH START');
     Stopwatch stopwatch = new Stopwatch();
     stopwatch.start();
     int testsFailed = 0;
     int totalTests = 0;
     ErrorSeverity batchResult = ErrorSeverity.NONE;
     // read line from stdin
     Stream cmdLine = stdin
-        .transform(new StringDecoder())
+        .transform(UTF8.decoder)
         .transform(new LineSplitter());
     var subscription = cmdLine.listen((String line) {
       // may be finish
       if (line.isEmpty) {
         var time = stopwatch.elapsedMilliseconds;
         stdout.writeln('>>> BATCH END (${totalTests - testsFailed}/$totalTests) ${time}ms');
         exit(batchResult.ordinal);
       }
       // prepare aruments
       var args;
@@ skipping 22 matching lines @@
         stdout.writeln('>>> TEST $resultPassString ${stopwatch.elapsedMilliseconds}ms');
       } catch (e, stackTrace) {
         stderr.writeln(e);
         stderr.writeln(stackTrace);
         stderr.writeln('>>> EOF STDERR');
         stdout.writeln('>>> TEST CRASH');
       }
     });
   }
 }