Add a snapshot of flutter/engine/src/build to our sdk

build/download_gold_plugin.py

Index: build/download_gold_plugin.py
diff --git a/build/download_gold_plugin.py b/build/download_gold_plugin.py
new file mode 100755
index 0000000000000000000000000000000000000000..cd7ca41ed312fe7774b622d163a8700e366b0bde
--- /dev/null
+++ b/build/download_gold_plugin.py
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+#!/usr/bin/env python
+# 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.
+
+"""Script to download LLVM gold plugin from google storage."""
+
+import json
+import os
+import shutil
+import subprocess
+import sys
+import zipfile
+
+SCRIPT_DIR = os.path.dirname(os.path.realpath(__file__))
+CHROME_SRC = os.path.abspath(os.path.join(SCRIPT_DIR, os.pardir))
+sys.path.insert(0, os.path.join(CHROME_SRC, 'tools'))
+
+import find_depot_tools
+
+DEPOT_PATH = find_depot_tools.add_depot_tools_to_path()
+GSUTIL_PATH = os.path.join(DEPOT_PATH, 'gsutil.py')
+
+LLVM_BUILD_PATH = os.path.join(CHROME_SRC, 'third_party', 'llvm-build',
+                               'Release+Asserts')
+CLANG_UPDATE_PY = os.path.join(CHROME_SRC, 'tools', 'clang', 'scripts',
+                               'update.py')
+CLANG_REVISION = os.popen(CLANG_UPDATE_PY + ' --print-revision').read().rstrip()
+
+CLANG_BUCKET = 'gs://chromium-browser-clang/Linux_x64'
+
+def main():
+  targz_name = 'llvmgold-%s.tgz' % CLANG_REVISION
+  remote_path = '%s/%s' % (CLANG_BUCKET, targz_name)
+
+  os.chdir(LLVM_BUILD_PATH)
+
+  subprocess.check_call(['python', GSUTIL_PATH,
+                         'cp', remote_path, targz_name])
+  subprocess.check_call(['tar', 'xzf', targz_name])
+  os.remove(targz_name)
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main())