Extension docs: Include sidenav in 404 pages

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

 # 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.
 
 from fnmatch import fnmatch
 import mimetypes
 import os
 
 from file_system import FileNotFoundError
 import compiled_file_system as compiled_fs
@@ skipping 53 matching lines @@
     elif path.startswith('static/'):
       content = self._FetchStaticResource(path, response)
     elif path.endswith('.html'):
       content = templates.Render(path)
 
     response.headers['x-frame-options'] = 'sameorigin'
     if content:
       response.headers['cache-control'] = 'max-age=300'
       response.out.write(content)
     else:
-      response.set_status(404);
-      response.out.write(templates.Render('404'))
+      response.set_status(404)
+      doc_class = path.split('/', 1)[0]
+      content = templates.Render(doc_class + '/404')
+      if not content:
+        content = templates.Render('extensions/404')
+      response.out.write(content)