Clean up dart:io warnings/errors found by analyzer tests.

sdk/lib/io/http_impl.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.
 
 part of dart.io;
 
 class _HttpIncoming extends Stream<List<int>> {
   final int _transferLength;
   final Completer _dataCompleter = new Completer();
   Stream<List<int>> _stream;
@@ skipping 618 matching lines @@
       return _outbound._close().then((_) => _outbound);
     }
     if (_controller == null) return closeOutbound();
     _controller.close();
     return _closeCompleter.future.then((_) => closeOutbound());
   }
 }
 
 
 class _BufferTransformer extends StreamEventTransformer<List<int>, List<int>> {
-  const int MIN_CHUNK_SIZE = 4 * 1024;
-  const int MAX_BUFFER_SIZE = 16 * 1024;
+  static const int MIN_CHUNK_SIZE = 4 * 1024;
+  static const int MAX_BUFFER_SIZE = 16 * 1024;
 
   final _BufferList _buffer = new _BufferList();
 
   void handleData(List<int> data, EventSink<List<int>> sink) {
     // TODO(ajohnsen): Use timeout?
     if (data.length == 0) return;
     if (data.length >= MIN_CHUNK_SIZE) {
       flush(sink);
       sink.add(data);
     } else {
@@ skipping 1730 matching lines @@
   final Uri location;
 }
 
 String _getHttpVersion() {
   var version = Platform.version;
   // Only include major and minor version numbers.
   int index = version.indexOf('.', version.indexOf('.') + 1);
   version = version.substring(0, index);
   return 'Dart/$version (dart:io)';
 }