Call `gzip` in subprocess instead of gzipping in Python in http_server.

mojo/devtools/common/devtoolslib/http_server.py

 # Copyright 2015 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.
 
 import atexit
 import datetime
 import email.utils
 import errno
-import gzip
 import hashlib
 import logging
 import math
 import os.path
-import shutil
 import socket
+import subprocess
+import tempfile
 import threading
-import tempfile
 
 import SimpleHTTPServer
 import SocketServer
 
 _ZERO = datetime.timedelta(0)
 
 
 class UTC_TZINFO(datetime.tzinfo):
   """UTC time zone representation."""
 
@@ skipping 120 matching lines @@
       for prefix, local_base_path_list in mappings:
         if normalized_path.startswith(prefix):
           for local_base_path in local_base_path_list:
             candidate = os.path.join(local_base_path,
                                      normalized_path[len(prefix):])
             if os.path.isfile(candidate):
               if gzipped:
                 if not self.gzipped_file:
                   self.gzipped_file = tempfile.NamedTemporaryFile(delete=False)
                   self.original_file_name = candidate
-                  with open(candidate, 'rb') as source:
-                    with gzip.GzipFile(fileobj=self.gzipped_file) as target:
-                      shutil.copyfileobj(source, target)
+                  subprocess.check_call(['gzip', '-c', candidate],

[piotrt, 2015/08/25 09:23:36]

Maybe it would be good to handle errors here? the .check_call method 
will raise a CalledProcessError if the gzip fails.

[ppi, 2015/08/25 11:34:36]

Done.

+                                        stdout=self.gzipped_file)
                   self.gzipped_file.close()
                 return self.gzipped_file.name
               return candidate
           else:
             self.send_response(404)
             return None
       self.send_response(404)
       return None
 
     def guess_type(self, path):
@@ skipping 49 matching lines @@
   except socket.error as v:
     error_code = v[0]
     print 'Failed to start http server for %s on port %d: %s.' % (
         str(mappings), host_port, os.strerror(error_code))
     if error_code == errno.EADDRINUSE:
       print ('  Run `fuser %d/tcp` to find out which process is using the port;'
              % host_port)
       print ('  or `fuser -k %d/tcp` terminate it.' % host_port)
     print '---'
     raise