gn2bp: add copy of perfetto project gn to bp tooling

This will serve as a starting point to generate Android.bp files for
cronet.

Test: n/a
Change-Id: Ia5ccad48f705fd48cff212dbedbfb61b6e385468
diff --git a/tools/gn2bp/run_buildtools_binary.py b/tools/gn2bp/run_buildtools_binary.py
new file mode 100755
index 0000000..7a6fe81
--- /dev/null
+++ b/tools/gn2bp/run_buildtools_binary.py
@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+# Copyright (C) 2022 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+""" A wrapper to run gn, ninja and other buildtools/ for all platforms. """
+
+from __future__ import print_function
+
+import os
+import subprocess
+import sys
+
+from platform import system, machine
+
+ROOT_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+def run_buildtools_binary(args):
+  if len(args) < 1:
+    print('Usage %s command [args]\n' % sys.argv[0])
+    return 1
+
+  sys_name = system().lower()
+  os_dir = None
+  ext = ''
+  if sys_name == 'windows':
+    os_dir = 'win'
+    ext = '.exe'
+  elif sys_name == 'darwin':
+    os_dir = 'mac'
+  elif sys_name == 'linux':
+    os_dir = 'linux64'
+  else:
+    print('OS not supported: %s\n' % sys_name)
+    return 1
+
+  cmd = args[0]
+  args = args[1:]
+  exe_path = os.path.join(ROOT_DIR, 'buildtools', os_dir, cmd) + ext
+  if sys_name == 'windows':
+    # execl() behaves oddly on Windows: the spawned process doesn't seem to
+    # receive CTRL+C. Use subprocess instead.
+    return subprocess.call([exe_path] + args)
+  else:
+    os.execl(exe_path, os.path.basename(exe_path), *args)
+
+
+if __name__ == '__main__':
+  sys.exit(run_buildtools_binary(sys.argv[1:]))