Use the hermetic toolchain if FORCE_MAC_TOOLCHAIN is set.

build/mac/should_use_hermetic_xcode.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
+"""Prints "1" if Chrome targets should be built with hermetic xcode. Otherwise
+prints "0"."""
+
 import os
 import sys
 
-import media_router_config
 
-sys.path.insert(1, media_router_config.TELEMETRY_DIR)
+def main():
+  if os.environ.get('FORCE_MAC_TOOLCHAIN'):
+    return "1"
+  else:
+    return "0"
 
-from telemetry import benchmark_runner
 
 if __name__ == '__main__':
-  sys.exit(benchmark_runner.main(media_router_config.Config(
-           ['benchmarks'])))
+  print main()
+  sys.exit(0)