[Downloads] Update origin info after each response.

net/tools/testserver/testserver.py

 #!/usr/bin/env python
 # Copyright 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """This is a simple HTTP/FTP/TCP/UDP/BASIC_AUTH_PROXY/WEBSOCKET server used for
 testing Chrome.
 
 It supports several test URLs, as specified by the handlers in TestPageHandler.
 By default, it listens on an ephemeral port and sends the port number back to
@@ skipping 1542 matching lines @@
 
     if range_response:
       self.send_response(206)
       self.send_header('Content-Range',
                        'bytes %d-%d/%d' % (first_byte, last_byte, size))
     else:
       self.send_response(200)
     self.send_header('Content-Type', 'application/octet-stream')
     self.send_header('Content-Length', last_byte - first_byte + 1)
     if send_verifiers:
-      self.send_header('Etag', '"XYZZY"')
+      # If fail_precondition is non-zero, then the ETag for each request will be
+      # different.
+      etag = "%s%d" % (token, fail_precondition)
+      self.send_header('ETag', etag)
       self.send_header('Last-Modified', 'Tue, 19 Feb 2013 14:32 EST')
     self.end_headers()
 
     if hold_for_signal:
       # TODO(rdsmith/phajdan.jr): http://crbug.com/169519: Without writing
       # a single byte, the self.server.handle_request() below hangs
       # without processing new incoming requests.
       self.wfile.write(DataForRange(first_byte, first_byte + 1))
       first_byte = first_byte + 1
       # handle requests until one of them clears this flag.
@@ skipping 523 matching lines @@
                                   '"aes128", "3des", "rc4". If omitted, all '
                                   'algorithms will be used. This option may '
                                   'appear multiple times, indicating '
                                   'multiple algorithms should be enabled.');
     self.option_parser.add_option('--file-root-url', default='/files/',
                                   help='Specify a root URL for files served.')
 
 
 if __name__ == '__main__':
   sys.exit(ServerRunner().main())