Add flush to HTTP output streams

runtime/bin/http_impl.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 1016 matching lines @@
   bool _streamWrite(List<int> buffer, bool copyBuffer) {
     if (_done) throw new HttpException("Response closed");
     return _write(buffer, copyBuffer);
   }
 
   bool _streamWriteFrom(List<int> buffer, int offset, int len) {
     if (_done) throw new HttpException("Response closed");
     return _writeList(buffer, offset, len);
   }
 
+  void _streamFlush() {
+    _httpConnection._flush();
+  }
+
   void _streamClose() {
     _responseEnd();
   }
 
   void _streamSetNoPendingWriteHandler(callback()) {
     if (_state != DONE) {
       _httpConnection._onNoPendingWrites = callback;
     }
   }
 
@@ skipping 143 matching lines @@
   void set onError(void callback(e)) {
     _requestOrResponse._streamSetErrorHandler(callback);
   }
 
   int _readInto(List<int> buffer, int offset, int len) {
     int result = _requestOrResponse._streamReadInto(buffer, offset, len);
     _checkScheduleCallbacks();
     return result;
   }
 
-  void flush() {
-    // Nothing to do on a HTTP output stream.
-  }
-
   void _close() {
     // TODO(sgjesse): Handle this.
   }
 
   void _dataReceived() {
     super._dataReceived();
   }
 
   _HttpRequestResponseBase _requestOrResponse;
 }
 
 
 class _HttpOutputStream extends _BaseOutputStream implements OutputStream {
   _HttpOutputStream(_HttpRequestResponseBase this._requestOrResponse);
 
   bool write(List<int> buffer, [bool copyBuffer = true]) {
     return _requestOrResponse._streamWrite(buffer, copyBuffer);
   }
 
   bool writeFrom(List<int> buffer, [int offset = 0, int len]) {
     return _requestOrResponse._streamWriteFrom(buffer, offset, len);
   }
 
+  void flush() {
+    _requestOrResponse._streamFlush();
+  }
+
   void close() {
     _requestOrResponse._streamClose();
   }
 
   bool get closed => _requestOrResponse._done;
 
   void destroy() {
     throw "Not implemented";
   }
 
@@ skipping 35 matching lines @@
       return _socket.outputStream.write(data, copyBuffer);
     }
   }
 
   bool _writeFrom(List<int> buffer, [int offset, int len]) {
     if (!_error && !_closing) {
       return _socket.outputStream.writeFrom(buffer, offset, len);
     }
   }
 
+  bool _flush() {
+    _socket.outputStream.flush();
+  }
+
   bool _close() {
     _closing = true;
     _socket.outputStream.close();
   }
 
   bool _destroy() {
     _closing = true;
     _socket.close();
   }
 
@@ skipping 348 matching lines @@
   bool _streamWrite(List<int> buffer, bool copyBuffer) {
     if (_done) throw new HttpException("Request closed");
     return _write(buffer, copyBuffer);
   }
 
   bool _streamWriteFrom(List<int> buffer, int offset, int len) {
     if (_done) throw new HttpException("Request closed");
     return _writeList(buffer, offset, len);
   }
 
+  void _streamFlush() {
+    _httpConnection._flush();
+  }
+
   void _streamClose() {
     _ensureHeadersSent();
     _state = DONE;
     // Stop tracking no pending write events.
     _httpConnection._onNoPendingWrites = null;
     // Ensure that any trailing data is written.
     _writeDone();
   }
 
   void _streamSetNoPendingWriteHandler(callback()) {
@@ skipping 928 matching lines @@
 
 
 class _RedirectInfo implements RedirectInfo {
   const _RedirectInfo(int this.statusCode,
                       String this.method,
                       Uri this.location);
   final int statusCode;
   final String method;
   final Uri location;
 }