Fix python scripts in src/tools/

tools/include_tracer.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.
 # based on an almost identical script by: jyrki@google.com (Jyrki Alakuijala)
-#
-# This script prints out include dependencies in chrome. Since it ignores
-# defines, it gives just a rough estimation of file size.
-#
-# Usage:
-#   python tools/include_tracer.py chrome/browser/ui/browser.h
+
+"""Prints out include dependencies in chrome.
+
+Since it ignores defines, it gives just a rough estimation of file size.
+
+Usage:
+  tools/include_tracer.py chrome/browser/ui/browser.h
+"""
 
 import os
 import sys
 
 # Created by copying the command line for prerender_browsertest.cc, replacing
 # spaces with newlines, and dropping everything except -F and -I switches.
 # TODO(port): Add windows, linux directories.
 INCLUDE_PATHS = [
   '',
   'gpu',
@@ skipping 165 matching lines @@
     elif line.startswith('#include '):
       include = '<' + line.split('<')[1].split('>')[0] + '>'
       total_bytes += Walk(
           seen, include, resolved_filename, indent + 2)
     elif line.startswith('import '):
       total_bytes += Walk(
           seen, line.split('"')[1], resolved_filename, indent + 2)
   return total_bytes + len("".join(lines))
 
 
-bytes = Walk(set(), sys.argv[1], '', 0)
-print
-print float(bytes) / (1 << 20), "megabytes of chrome source"
+def main():
+  bytes = Walk(set(), sys.argv[1], '', 0)
+  print
+  print float(bytes) / (1 << 20), "megabytes of chrome source"
+
+
+if __name__ == '__main__':
+  sys.exit(main())