webkitpy: Refactor _stop_running_server for wptserve

third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/servers/wptserve.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.
 
 """Start and stop the WPTserve servers as they're used by the layout tests."""
 
 import datetime
 import logging
 from webkitpy.layout_tests.servers import server_base
 
@@ skipping 42 matching lines @@
         self._start_cmd = start_cmd
 
         expiration_date = datetime.date(2025, 1, 4)
         if datetime.date.today() > expiration_date - datetime.timedelta(30):
             logging.getLogger(__name__).error(
                 'Pre-generated keys and certificates are going to be expired at %s.'
                 ' Please re-generate them by following steps in %s/README.chromium.'
                 % (expiration_date.strftime('%b %d %Y'), path_to_wpt_support))
 
     def _stop_running_server(self):
+        while self._pid and self._executive.check_running_pid(self._pid):
+            # TODO(burnik): Figure out a cleaner way of stopping wptserve.
+            if self._platform.is_win():
+                self._executive.kill_process(self._pid)
+            else:
+                self._executive.interrupt(self._pid)
+
+            # According to Popen.wait(), this can deadlock when using stdout=PIPE and/or stderr=PIPE.
+            # We're using DEVNULL for both so that should not occur.
+            if self._process is not None:
+                self._process.wait()
+
         # Clean up the pid file.
-        if self._pid and not self._executive.check_running_pid(self._pid):
+        if self._filesystem.exists(self._pid_file):
             self._filesystem.remove(self._pid_file)
-            return
-
-        # TODO(burnik): Figure out a cleaner way of stopping wptserve.
-        if self._platform.is_win():
-            self._executive.kill_process(self._pid)
-        else:
-            self._executive.interrupt(self._pid)
-
-        # According to Popen.wait(), this can deadlock when using stdout=PIPE and/or stderr=PIPE.
-        # We're using DEVNULL for both so that should not occur.
-        self._process.wait()