Revert of Add gclient hook to download prebuilt mojo_shell

mojo/public/tools/download_shell_binary.py

-#!/usr/bin/env python
-# Copyright 2014 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 os
-import subprocess
-import sys
-import tempfile
-import zipfile
-
-current_path = os.path.dirname(os.path.realpath(__file__))
-sys.path.insert(0, os.path.join(current_path, "..", "..", "..", "tools"))
-# pylint: disable=F0401
-import find_depot_tools
-
-if not sys.platform.startswith("linux"):
-  print "Not supported for your platform"
-  sys.exit(0)
-
-version_path = os.path.join(current_path, "../VERSION")
-with open(version_path) as version_file:
-  version = version_file.read().strip()
-
-prebuilt_file_path = os.path.join(current_path, "prebuilt")
-stamp_path = os.path.join(prebuilt_file_path, "VERSION")
-
-try:
-  with open(stamp_path) as stamp_file:
-    current_version = stamp_file.read().strip()
-    if current_version == version:
-      sys.exit(0)
-except IOError:
-  pass
-
-platform = "linux-x64" # TODO: configurate
-basename = platform + ".zip"
-
-gs_path = "gs://mojo/shell/" + version + "/" + basename
-
-depot_tools_path = find_depot_tools.add_depot_tools_to_path()
-gsutil_exe = os.path.join(depot_tools_path, "third_party", "gsutil", "gsutil")
-
-with tempfile.NamedTemporaryFile() as temp_zip_file:
-  subprocess.check_call([gsutil_exe, "cp", gs_path, temp_zip_file.name])
-  with zipfile.ZipFile(temp_zip_file.name) as z:
-    zi = z.getinfo("mojo_shell")
-    mode = zi.external_attr >> 16L
-    z.extract(zi, prebuilt_file_path)
-    os.chmod(os.path.join(prebuilt_file_path, "mojo_shell"), mode)
-
-with open(stamp_path, 'w') as stamp_file:
-  stamp_file.write(version + "\n")