Make the fuchsia mojo/public repo the source of truth.

mojo/public/tools/pylib/gs.py

-# Copyright 2015 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
-
-def download_from_public_bucket(gs_path, output_path, depot_tools_path):
-  gsutil_exe = os.path.join(depot_tools_path, "third_party", "gsutil", "gsutil")
-
-  # We're downloading from a public bucket which does not need authentication,
-  # but the user might have busted credential files somewhere such as ~/.boto
-  # that the gsutil script will try (and fail) to use. Setting these
-  # environment variables convinces gsutil not to attempt to use these, but
-  # also generates a useless warning about failing to load the file. We want
-  # to discard this warning but still preserve all output in the case of an
-  # actual failure. So, we run the script and capture all output and then
-  # throw the output away if the script succeeds (return code 0).
-  env = os.environ.copy()
-  env["AWS_CREDENTIAL_FILE"] = ""
-  env["BOTO_CONFIG"] = ""
-  try:
-    subprocess.check_output(
-        [gsutil_exe,
-         "--bypass_prodaccess",
-         "cp",
-         gs_path,
-         output_path],
-        stderr=subprocess.STDOUT,
-        env=env)
-  except subprocess.CalledProcessError as e:
-    print e.output
-    sys.exit(1)