Change the HTTP Content-Length handling

sdk/lib/io/http_headers.dart

 // Copyright (c) 2012, 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.
 
 class _HttpHeaders implements HttpHeaders {
   _HttpHeaders() : _headers = new Map<String, List<String>>();
 
   List<String> operator[](String name) {
     name = name.toLowerCase();
     return _headers[name];
@@ skipping 47 matching lines @@
 
   void forEach(void f(String name, List<String> values)) {
     _headers.forEach(f);
   }
 
   void noFolding(String name) {
     if (_noFoldingHeaders == null) _noFoldingHeaders = new List<String>();
     _noFoldingHeaders.add(name);
   }
 
+  int get contentLength => _contentLength;
+
+  void set contentLength(int contentLength) {
+    _checkMutable();
+    _contentLength = contentLength;
+    if (_contentLength >= 0) {
+      _set("content-length", contentLength.toString());
+    } else {
+      removeAll("content-length");
+    }
+  }
+
   String get host => _host;
 
   void set host(String host) {
     _checkMutable();
     _host = host;
     _updateHostHeader();
   }
 
   int get port => _port;
 
@@ skipping 70 matching lines @@
   }
 
   void set contentType(ContentType contentType) {
     _checkMutable();
     _set("content-type", contentType.toString());
   }
 
   void _add(String name, Object value) {
     var lowerCaseName = name.toLowerCase();
     // TODO(sgjesse): Add immutable state throw HttpException is immutable.
-    if (lowerCaseName == "date") {
+    if (lowerCaseName == "content-length") {
+      if (value is int) {
+        contentLength = value;
+      } else if (value is String) {
+        contentLength = parseInt(value);
+      } else {
+        throw new HttpException("Unexpected type for header named $name");
+      }
+    } else if (lowerCaseName == "date") {
       if (value is Date) {
         date = value;
       } else if (value is String) {
         _set("date", value);
       } else {
         throw new HttpException("Unexpected type for header named $name");
       }
     } else if (lowerCaseName == "expires") {
       if (value is Date) {
         expires = value;
@@ skipping 147 matching lines @@
       }
       sb.add("\n");
     });
     return sb.toString();
   }
 
   bool _mutable = true;  // Are the headers currently mutable?
   Map<String, List<String>> _headers;
   List<String> _noFoldingHeaders;
 
+  int _contentLength = -1;
   String _host;
   int _port;
 }
 
 
 class _HeaderValue implements HeaderValue {
   _HeaderValue([String this.value = ""]);
 
   _HeaderValue.fromString(String value, {this.parameterSeparator: ";"}) {
     // Parse the string.
@@ skipping 283 matching lines @@
 
   String name;
   String value;
   Date expires;
   int maxAge;
   String domain;
   String path;
   bool httpOnly = false;
   bool secure = false;
 }