[infra] Roll clang to match the version used by Flutter

tools/buildtools/update.py

+#!/usr/bin/env python
+# Copyright 2017 The Dart project authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Pulls down tools required to build Dart."""
+
+import os
+import subprocess
+import shutil
+import sys
+
+THIS_DIR = os.path.abspath(os.path.dirname(__file__))
+DART_ROOT = os.path.abspath(os.path.join(THIS_DIR, '..', '..'))
+BUILDTOOLS = os.path.join(DART_ROOT, 'buildtools')
+TOOLS_BUILDTOOLS = os.path.join(DART_ROOT, 'tools', 'buildtools')
+
+sys.path.insert(0, os.path.join(DART_ROOT, 'tools'))
+import find_depot_tools
+
+DEPOT_PATH = find_depot_tools.add_depot_tools_to_path()
+
+
+def Update():
+  path = os.path.join(BUILDTOOLS, 'update.sh')
+  return subprocess.call(['/bin/bash', path, '--toolchain', '--gn'], cwd=DART_ROOT)
+
+
+def UpdateGNOnWindows():
+  sha1_file = os.path.join(BUILDTOOLS, 'win', 'gn.exe.sha1')
+  downloader_script = os.path.join(DEPOT_PATH, 'download_from_google_storage.py')
+  download_cmd = [
+    'python',
+    downloader_script,
+    '--no_auth',
+    '--no_resume',
+    '--quiet',
+    '--platform=win*',
+    '--bucket',
+    'chromium-gn',
+    '-s',
+    sha1_file
+  ]
+  return subprocess.call(download_cmd)
+
+
+def UpdateClangFormatOnWindows():
+  sha1_file = os.path.join(TOOLS_BUILDTOOLS, 'win', 'clang-format.exe.sha1')
+  output_dir = os.path.join(BUILDTOOLS, 'win', 'clang-format.exe')
+  downloader_script = os.path.join(DEPOT_PATH, 'download_from_google_storage.py')
+  download_cmd = [
+    'python',
+    downloader_script,
+    '--no_auth',
+    '--no_resume',
+    '--quiet',
+    '--platform=win',
+    '--bucket',
+    'chromium-clang-format',
+    '-s',
+    sha1_file,
+    '-o',
+    output_dir
+  ]
+  return subprocess.call(download_cmd)
+
+
+def CopyClangFormatScripts():
+  linux_script = os.path.join(TOOLS_BUILDTOOLS, 'linux64', 'clang-format')
+  mac_script = os.path.join(TOOLS_BUILDTOOLS, 'mac', 'clang-format')
+  linux_dest = os.path.join(BUILDTOOLS, 'linux64', 'clang-format')
+  mac_dest = os.path.join(BUILDTOOLS, 'mac', 'clang-format')
+  shutil.copy2(linux_script, linux_dest)
+  shutil.copy2(mac_script, mac_dest)
+
+
+def main(argv):
+  if sys.platform.startswith('win'):
+    result = UpdateGNOnWindows()
+    if result != 0:
+      return result
+    return UpdateClangFormatOnWindows()
+  CopyClangFormatScripts()
+  return Update()
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))