Fix python scripts in src/tools/

tools/crx_id/crx_id.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.
 
 """ Read a CRX file and write out the App ID and the Full Hash of the ID.
 See: http://code.google.com/chrome/extensions/crx.html
 and 'http://stackoverflow.com/questions/'
   + '1882981/google-chrome-alphanumeric-hashes-to-identify-extensions'
 for docs on the format.
 """
 
 import sys
 import hashlib
 
+
+EXPECTED_CRX_MAGIC_NUM = 'Cr24'
+EXPECTED_CRX_VERSION = 2
+
+
 def usage(argv):
   print "%s: crx_file" % argv[0]
 
-EXPECTED_CRX_MAGIC_NUM = 'Cr24'
-EXPECTED_CRX_VERSION = 2
-
 def HexToInt(hex_chars):
   """ Convert bytes like \xab -> 171 """
   val = 0
   for i in xrange(len(hex_chars)):
     val += pow(256, i) * ord(hex_chars[i])
   return val
 
 def HexToMPDecimal(hex_chars):
   """ Convert bytes to an MPDecimal string. Example \x00 -> "aa"
       This gives us the AppID for a chrome extension.
@@ skipping 42 matching lines @@
   return HexTo256(pub_key_hash)
 
 def GetCRXAppID(filename):
   f = open(filename, 'rb')
   pub_key = GetPublicKey(f)
   f.close()
   pub_key_hash = hashlib.sha256(pub_key).digest()
   # AppID is the MPDecimal of only the first 128 bits of the hash.
   return HexToMPDecimal(pub_key_hash[:128/8])
 
+
 def main(argv):
   if len(argv) != 2:
     usage(argv)
     return 1
   print 'Raw Bytes: %s' % GetCRXHash(sys.argv[1])
   print 'AppID: %s' % GetCRXAppID(sys.argv[1])
 
+
 if __name__ == '__main__':
   sys.exit(main(sys.argv))