Skip running GYP if GYP_CHROMIUM_NO_ACTION is set in environment

gyp_libyuv

 #!/usr/bin/env python
 #
 # Copyright 2014 The LibYuv 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 in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS. All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
@@ skipping 19 matching lines @@
   """Returns a list of the supplemental files that are included in all GYP
   sources."""
   # Can't use the one in gyp_chromium since the directory location of the root
   # is different.
   return glob.glob(os.path.join(checkout_root, '*', 'supplement.gypi'))
 
 
 if __name__ == '__main__':
   args = sys.argv[1:]
 
+  if int(os.environ.get('GYP_CHROMIUM_NO_ACTION', 0)):
+    print 'Skipping gyp_libyuv due to GYP_CHROMIUM_NO_ACTION env var.'
+    sys.exit(0)
+
   # This could give false positives since it doesn't actually do real option
   # parsing.  Oh well.
   gyp_file_specified = False
   for arg in args:
     if arg.endswith('.gyp'):
       gyp_file_specified = True
       break
 
   # If we didn't get a file, assume 'all.gyp' in the root of the checkout.
   if not gyp_file_specified:
@@ skipping 38 matching lines @@
   # Off we go...
   gyp_rc = gyp.main(args)
 
   if vs2013_runtime_dll_dirs:
     x64_runtime, x86_runtime = vs2013_runtime_dll_dirs
     vs_toolchain.CopyVsRuntimeDlls(
         os.path.join(checkout_root, gyp_chromium.GetOutputDirectory()),
         (x86_runtime, x64_runtime))
 
   sys.exit(gyp_rc)