Prevent hanging if selenium cannot close browser.

dart/tools/testing/run_selenium.py

 #!/usr/bin/python
 
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 #
 
 """Script to actually open a browser and perform the test, and reports back with
 the result. It uses Selenium WebDriver when possible for running the tests. It
 uses Selenium RC for Safari.
@@ skipping 22 matching lines @@
 import selenium
 from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
 from selenium.webdriver.remote.webdriver import WebDriver as RemoteWebDriver
 from selenium.webdriver.support.ui import WebDriverWait
 import shutil
 import signal
 import socket
 import sys
 import time
 import urllib2
+import threading
 
 TIMEOUT_ERROR_MSG = 'FAIL (timeout)'
 
 def correctness_test_done(source):
   """Checks if test has completed."""
   return ('PASS' in source) or ('FAIL' in source)
 
 def perf_test_done(source):
   """Tests to see if our performance test is done by printing a score."""
   #This code is written this way to work around a current instability in the
@@ skipping 255 matching lines @@
       # >>> TEST {PASS, FAIL, OK, CRASH, FAIL, TIMEOUT}
       status = report_results(mode, source, browser)
       if status == 0:
         print '>>> TEST PASS'
       elif source == TIMEOUT_ERROR_MSG:
         print '>>> TEST TIMEOUT'
       else:
         print '>>> TEST FAIL'
       sys.stdout.flush()
   finally:
+    sys.stdin.close()
     print("Closing browser");
-    close_browser(browser)
 
+    def close_output_streams:
+      sys.stdout.flush()
+      sys.stdout.close()
+      sys.stderr.flush()
+      sys.stderr.close()
+
+    def close_and_exit:
+      print("Timed out waiting for browser to close")
+      close_output_streams()
+      exit(1)
+
+    timer = threading.Timer(5.0, close_and_exit)
+    timer.start()
+    try:
+      close_browser(browser)
+      timer.cancel()
+    finally:
+      close_output_streams()
 
 def main(args):
   # Run in batch mode if the --batch flag is passed.
   # TODO(jmesserly): reconcile with the existing args parsing
   if '--batch' in args:
     return run_batch_tests()
 
   # Run a single test
   html_out, browser_name, executable_path, timeout, mode = parse_args()
   browser = start_browser(browser_name, executable_path, html_out)
 
   try:
     output = run_test_in_browser(browser, html_out, timeout, mode)
     return report_results(mode, output, browser)
   finally:
     close_browser(browser)
 
 if __name__ == "__main__":
   sys.exit(main(sys.argv))