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

tools/ddbg.dart

Index: tools/ddbg.dart
diff --git a/tools/ddbg.dart b/tools/ddbg.dart
index 18673a6dcb95f2c9bea96d3043fa8a831da566e0..17fb40bc40052d606bae0d43e9b89ca15ade9529 100644
--- a/tools/ddbg.dart
+++ b/tools/ddbg.dart
@@ -5,6 +5,7 @@
 // Simple interactive debugger shell that connects to the Dart VM's debugger
 // connection port.
 
+import "dart:convert";
 import "dart:io";
 import "dart:json" as json;
 import "dart:utf";
@@ -590,7 +591,7 @@ void debuggerMain() {
   Socket.connect("127.0.0.1", 5858).then((s) {
     vmSock = s;
     vmSock.setOption(SocketOption.TCP_NODELAY, true);
-    var stringStream = vmSock.transform(new StringDecoder());
+    var stringStream = vmSock.transform(UTF8.decoder);
     vmSubscription = stringStream.listen(
         (String data) {
           processVmData(data);
@@ -604,8 +605,8 @@ void debuggerMain() {
           // TODO(floitsch): do we want to print the stack trace?
           quitShell();
         });
-    stdinSubscription = stdin.transform(new StringDecoder())
-                             .transform(new LineTransformer())
+    stdinSubscription = stdin.transform(UTF8.decoder)
+                             .transform(new LineSplitter())
                              .listen((String line) => processCommand(line));
   });
 }