Fix python scripts in src/tools/

tools/valgrind/asan/chrome_tests.py

-#!/usr/bin/python
-
+#!/usr/bin/env python
 # Copyright (c) 2011 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.
 
 ''' Runs various chrome tests through asan_test.py.
 
 Most of this code is copied from ../valgrind/chrome_tests.py.
 TODO(glider): put common functions to a standalone module.
 '''
 
@@ skipping 396 matching lines @@
       f.close()
     except IOError, (errno, strerror):
       logging.error("error writing to file %s (%d, %s)" % (chunk_file, errno,
                     strerror))
 
     # Since we're running small chunks of the layout tests, it's important to
     # mark the ones that have errors in them.  These won't be visible in the
     # summary list for long, but will be useful for someone reviewing this bot.
     return ret
 
-def _main(_):
+
+def main():
+  if not sys.platform.startswith(('linux', 'darwin')):
+    logging.error("AddressSanitizer works only on Linux and Mac OS "
+                  "at the moment.")
+    return 1
   parser = optparse.OptionParser("usage: %prog -b <dir> -t <test> "
                                  "[-t <test> ...]")
   parser.disable_interspersed_args()
   parser.add_option("-b", "--build_dir",
                     help="the location of the output of the compiler output")
   parser.add_option("-t", "--test", action="append",
                     help="which test to run")
   parser.add_option("", "--gtest_filter",
                     help="additional arguments to --gtest_filter")
   parser.add_option("", "--gtest_repeat",
@@ skipping 19 matching lines @@
 
   for t in options.test:
     tests = ChromeTests(options, args, t)
     ret = tests.Run()
     if ret:
       return ret
   return 0
 
 
 if __name__ == "__main__":
-  if sys.platform.startswith('linux'):
-    ret = _main(sys.argv)
-  elif sys.platform.startswith('darwin'):
-    ret = _main(sys.argv)
-  else:
-    logging.error("AddressSanitizer works only on Linux and Mac OS "
-                  "at the moment.")
-    ret = 1
-  sys.exit(ret)
+  sys.exit(main())