Use the hermetic toolchain if FORCE_MAC_TOOLCHAIN is set.

build/mac/should_use_hermetic_xcode.py

Index: build/mac/should_use_hermetic_xcode.py
diff --git a/chrome/test/media_router/telemetry/run_benchmark b/build/mac/should_use_hermetic_xcode.py
similarity index 52%
copy from chrome/test/media_router/telemetry/run_benchmark
copy to build/mac/should_use_hermetic_xcode.py
index fb02300b43241fd3a724f8def66826230b03c9b6..9f4b25e00377d096ccd96238b17173093344ed3c 100755
--- a/chrome/test/media_router/telemetry/run_benchmark
+++ b/build/mac/should_use_hermetic_xcode.py
@@ -3,15 +3,20 @@
 # 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)