Fix python scripts in src/chrome/

chrome/tools/webforms_aggregator_unittests.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.
 
 import logging
 import os
 import subprocess
 import tempfile
 import unittest
 
@@ skipping 277 matching lines @@
     c = webforms_aggregator.ThreadedCrawler(self.files['url'])
     self.assertNotEqual(
         c.Run(), -1,
         msg='Threaded crawler could not find the reg page from the URLs file')
 
 
 if __name__ == '__main__':
   suite = unittest.TestLoader().loadTestsFromTestCase(
       WebformsAggregatorTest)
   unittest.TextTestRunner(verbosity=2).run(suite)