Docs: Use ETags.

chrome/common/extensions/docs/server2/preview.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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 helps you preview the apps and extensions docs.
 #
 #    ./preview.py --help
 #
 # There are two modes: server- and render- mode. The default is server, in which
@@ skipping 29 matching lines @@
 class _RequestHandler(BaseHTTPRequestHandler):
   '''A HTTPRequestHandler that outputs the docs page generated by Handler.
   '''
   def do_GET(self):
     # Rewrite paths that would otherwise be served from app.yaml.
     self.path = {
       '/robots.txt': '../../server2/robots.txt',
       '/favicon.ico': '../../server2/chrome-32.ico',
       '/apple-touch-icon-precomposed.png': '../../server2/chrome-128.png'
     }.get(self.path, self.path)
-    response = LocalRenderer.Render(self.path)
+    response = LocalRenderer.Render(self.path, headers=dict(self.headers))
+    self.protocol_version = 'HTTP/1.1'
     self.send_response(response.status)
     for k, v in response.headers.iteritems():
       self.send_header(k, v)
     self.end_headers()
     self.wfile.write(response.content.ToString())
 
 if __name__ == '__main__':
   parser = optparse.OptionParser(
       description='Runs a server to preview the extension documentation.',
       usage='usage: %prog [option]...')
@@ skipping 44 matching lines @@
   print('')
   print('  http://localhost:%s/apps/' % opts.port)
   print('')
 
   logging.getLogger().setLevel(logging.INFO)
   server = HTTPServer(('', int(opts.port)), _RequestHandler)
   try:
     server.serve_forever()
   finally:
     server.socket.close()