Move //tools/gs.py into //mojo/public/tools

mojo/public/tools/download_shell_binary.py

Index: mojo/public/tools/download_shell_binary.py
diff --git a/mojo/public/tools/download_shell_binary.py b/mojo/public/tools/download_shell_binary.py
index 30891c20e2f37ba5e38702bddea597e7b78ad9de..9841860db0eebd6f40eb8b06bb404bb94f24cb29 100755
--- a/mojo/public/tools/download_shell_binary.py
+++ b/mojo/public/tools/download_shell_binary.py
@@ -4,6 +4,7 @@
 # found in the LICENSE file.
 
 import argparse
+import gs
 import os
 import subprocess
 import sys
@@ -47,41 +48,13 @@ def download(tools_directory):
 
 def download_version_for_platform(version, platform, tools_directory):
   find_depot_tools_path = os.path.join(CURRENT_PATH, tools_directory)
-  sys.path.insert(0, find_depot_tools_path)
-  # pylint: disable=F0401
-  import find_depot_tools
 
   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:
-    # 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,
-           temp_zip_file.name],
-          stderr=subprocess.STDOUT,
-          env=env)
-    except subprocess.CalledProcessError as e:
-      print e.output
-      sys.exit(1)
-
+    gs.download_from_public_bucket(gs_path, temp_zip_file.name,
+                                   find_depot_tools_path)
     binary_name = BINARY_FOR_PLATFORM[platform]
     output_dir = os.path.join(PREBUILT_FILE_PATH, platform)
     with zipfile.ZipFile(temp_zip_file.name) as z:
@@ -103,7 +76,7 @@ def main():
                            " from the location of this file.")
   args = parser.parse_args()
   if not args.tools_directory:
-    print "Must specify --tools_directory; please see help message."
+    print "Must specify --tools-directory; please see help message."
     sys.exit(1)
   return download(args.tools_directory)