Give more debug info from selenium driver.

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 270 matching lines @@
   current_browser_name = None
 
   # TODO(jmesserly): It'd be nice to shutdown gracefully in the event of a
   # SIGTERM. Unfortunately dart:io cannot send SIGTERM, see dartbug.com/1756.
   signal.signal(signal.SIGTERM, lambda number, frame: close_browser(browser))
 
   try:
     while True:
       line = sys.stdin.readline()
       if line == '--terminate\n':
+        print("Terminating selenium driver")
         break
 
       (html_out, browser_name, executable_path,
        timeout, mode) = parse_args(line.split())
 
       # Sanity checks that test.dart is passing flags we can handle.
       if mode != 'correctness':
         print 'Batch test runner not compatible with perf testing'
         return 1
       if browser and current_browser_name != browser_name:
@@ skipping 16 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:
+    print("Closing browser");
     close_browser(browser)
 
 
 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))