Fix bug in caching of chunked transfer encoding in HTTP headers

tests/standalone/io/http_headers_test.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.
 
 library dart.io;
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:collection";
 import "dart:convert";
@@ skipping 168 matching lines @@
   Expect.equals(host, headers.host);
   Expect.isNull(headers.port);
 
   headers = new _HttpHeaders("1.1");
   headers.add(HttpHeaders.HOST, ":1234");
   Expect.equals(":1234", headers.value(HttpHeaders.HOST));
   Expect.isNull(headers.host);
   Expect.equals(1234, headers.port);
 }
 
+void testTransferEncoding() {
+  expectChunked(headers) {
+    Expect.listEquals(headers['transfer-encoding'], ['chunked']);
+    Expect.isTrue(headers.chunkedTransferEncoding);
+  }
+
+  expectNonChunked(headers) {
+    Expect.isNull(headers['transfer-encoding']);
+    Expect.isFalse(headers.chunkedTransferEncoding);
+  }
+
+  _HttpHeaders headers;
+
+  headers = new _HttpHeaders("1.1");
+  headers.chunkedTransferEncoding = true;
+  expectChunked(headers);
+  headers.set('transfer-encoding', ['chunked']);
+  expectChunked(headers);
+
+  headers = new _HttpHeaders("1.1");
+  headers.set('transfer-encoding', ['chunked']);
+  expectChunked(headers);
+  headers.chunkedTransferEncoding = true;
+  expectChunked(headers);
+
+  headers = new _HttpHeaders("1.1");
+  headers.chunkedTransferEncoding = true;
+  headers.chunkedTransferEncoding = false;
+  expectNonChunked(headers);
+
+  headers = new _HttpHeaders("1.1");
+  headers.chunkedTransferEncoding = true;
+  headers.remove('transfer-encoding', 'chunked');
+  expectNonChunked(headers);
+
+  headers = new _HttpHeaders("1.1");
+  headers.set('transfer-encoding', ['chunked']);
+  headers.chunkedTransferEncoding = false;
+  expectNonChunked(headers);
+
+  headers = new _HttpHeaders("1.1");
+  headers.set('transfer-encoding', ['chunked']);
+  headers.remove('transfer-encoding', 'chunked');
+  expectNonChunked(headers);
+}
+
 void testEnumeration() {
   _HttpHeaders headers = new _HttpHeaders("1.1");
   Expect.isNull(headers[HttpHeaders.PRAGMA]);
   headers.add("My-Header-1", "value 1");
   headers.add("My-Header-2", "value 2");
   headers.add("My-Header-1", "value 3");
   bool myHeader1 = false;
   bool myHeader2 = false;
   int totalValues = 0;
   headers.forEach((String name, List<String> values) {
@@ skipping 299 matching lines @@
   // Test we handle other types correctly.
   test(new StringBuffer('\x00'), remove: false);
 }
 
 main() {
   testMultiValue();
   testDate();
   testExpires();
   testIfModifiedSince();
   testHost();
+  testTransferEncoding();
   testEnumeration();
   testHeaderValue();
   testContentType();
   testContentTypeCache();
   testCookie();
   testInvalidCookie();
   testHeaderLists();
   testInvalidFieldName();
   testInvalidFieldValue();
 }