Move MimeMultipartTransformer and HttpBodyHandler to mime and http_server packages.

pkg/http_server/lib/src/http_body_impl.dart

Index: pkg/http_server/lib/src/http_body_impl.dart
diff --git a/sdk/lib/io/http_body_impl.dart b/pkg/http_server/lib/src/http_body_impl.dart
similarity index 91%
rename from sdk/lib/io/http_body_impl.dart
rename to pkg/http_server/lib/src/http_body_impl.dart
index 2eaf07bd791b9e66290e04a28621b464edb2929f..5d52874b1bd4baf89e8bd64ae278db467ad341df 100644
--- a/sdk/lib/io/http_body_impl.dart
+++ b/pkg/http_server/lib/src/http_body_impl.dart
@@ -2,7 +2,7 @@
 // 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;
+part of http_server;
 
 class _HttpBodyHandlerTransformer
     extends StreamEventTransformer<HttpRequest, HttpRequestBody> {
@@ -150,6 +150,24 @@ class _HttpBodyHandler {
 
     return asBinary();
   }
+
+  // Utility function to synchronously decode a list of bytes.
+  static String _decodeString(List<int> bytes,
+                              [Encoding encoding = Encoding.UTF_8]) {
+    if (bytes.length == 0) return "";
+    var string;
+    var error;
+    var controller = new StreamController(sync: true);
+    controller.stream
+      .transform(new StringDecoder(encoding))
+      .listen((data) => string = data,

[Bill Hesse, 2013/07/12 11:43:33]

What about an input that ends in half of an encoded character?

I would prefer 
.listen((data) => strings.add(data),
onError: ... ,
onDone: () => string = strings.join());

Then we are sure that the controller has sent close on its output stream.

[Anders Johnsen, 2013/07/15 08:21:32]

Yes, see line 166.

[Bill Hesse, 2013/07/15 08:26:33]

OK, so controller.close is guaranteed to synchronously close all the way
through, of course.

+              onError: (e) => error = e);
+    controller.add(bytes);
+    controller.close();
+    if (error != null) throw error;
+    assert(string != null);
+    return string;
+  }
 }
 
 class _HttpBodyFileUpload implements HttpBodyFileUpload {