Make gn_run_binary.py do the right thing for compiled_action

build/gn_run_binary.py

 #!/usr/bin/env python
 # Copyright 2014 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.
 
 """Helper script for GN to run an arbitrary binary. See compiled_action.gni.
 
 Run with:
-  python gn_run_binary.py <binary_name> [args ...]
+  python gn_run_binary.py <invoker> <binary_name> [args ...]
+
+Where <invoker> is either "compiled_action" or "exec_script". If it is
+"compiled_action" the script has a non-zero exit code on a failure. If it is
+"exec_script" the script has no output on success and produces output otherwise,
+but always has an exit code of 0.
 """
 
 import os
 import sys
 import subprocess
 
 # Run a command, swallowing the output unless there is an error.
 def run_command(command):
   try:
     subprocess.check_output(command, stderr=subprocess.STDOUT)
     return 0
   except subprocess.CalledProcessError as e:
     return ("Command failed: " + ' '.join(command) + "\n" +
             "output: " + e.output)
 
 def main(argv):
+  error_exit = 0
+  if argv[1] == "compiled_action":
+    error_exit = 1
+  elif argv[1] != "exec_script":
+    print ("The first argument should be either "
+           "'compiled_action' or 'exec_script")
+    return 1
+
   # Unless the path is absolute, this script is designed to run binaries
   # produced by the current build. We always prefix it with "./" to avoid
   # picking up system versions that might also be on the path.
-  if os.path.isabs(argv[1]):
-    path = argv[1]
+  if os.path.isabs(argv[2]):
+    path = argv[2]
   else:
-    path = './' + argv[1]
+    path = './' + argv[2]
 
   if not os.path.isfile(path):
     print "Binary not found: " + path
-    return 0
+    return error_exit
 
   # The rest of the arguements are passed directly to the executable.
-  args = [path] + argv[2:]
+  args = [path] + argv[3:]
 
   result = run_command(args)
   if result != 0:
     print result
+    return error_exit
   return 0
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv))