Fix python scripts in src/chrome/

chrome/nacl/nacl_helper_bootstrap_munge_phdr.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.
-#
-# This takes three command-line arguments:
-#       MUNGE-PHDR-PROGRAM      file name of program built from
-#                               nacl_helper_bootstrap_munge_phdr.c
-#       INFILE                  raw linked ELF file name
-#       OUTFILE                 output file name
-#
-# We just run the MUNGE-PHDR-PROGRAM on a copy of INFILE.
-# That modifies the file in place.  Then we move it to OUTFILE.
-#
-# We only have this wrapper script because nacl_helper_bootstrap_munge_phdr.c
-# wants to modify a file in place (and it would be a much longer and more
-# fragile program if it created a fresh ELF output file instead).
+
+"""This takes three command-line arguments:
+      MUNGE-PHDR-PROGRAM      file name of program built from
+                              nacl_helper_bootstrap_munge_phdr.c
+      INFILE                  raw linked ELF file name
+      OUTFILE                 output file name
+
+We just run the MUNGE-PHDR-PROGRAM on a copy of INFILE.
+That modifies the file in place.  Then we move it to OUTFILE.
+
+We only have this wrapper script because nacl_helper_bootstrap_munge_phdr.c
+wants to modify a file in place (and it would be a much longer and more
+fragile program if it created a fresh ELF output file instead).
+"""
 
 import shutil
 import subprocess
 import sys
 
 
 def Main(argv):
   if len(argv) != 4:
     print 'Usage: %s MUNGE-PHDR-PROGRAM INFILE OUTFILE' % argv[0]
-    sys.exit(1)
+    return 1
   [prog, munger, infile, outfile] = argv
   tmpfile = outfile + '.tmp'
   shutil.copy(infile, tmpfile)
   segment_num = '2'
   subprocess.check_call([munger, tmpfile, segment_num])
   shutil.move(tmpfile, outfile)
+  return 0
+
 
 if __name__ == '__main__':
-  Main(sys.argv)
+  sys.exit(Main(sys.argv))