Make landmines.py take an extra script via an env var.

build/landmines.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 """
 This script runs every build as a hook. If it detects that the build should
 be clobbered, it will touch the file <build_dir>/.landmine_triggered. The
 various build scripts will then check for the presence of this file and clobber
 accordingly. The script will also emit the reasons for the clobber to stdout.
@@ skipping 88 matching lines @@
   options, args = parser.parse_args()
 
   if args:
     parser.error('Unknown arguments %s' % args)
 
   logging.basicConfig(
       level=logging.DEBUG if options.verbose else logging.ERROR)
 
   gyp_helper.apply_chromium_gyp_env()
 
+  extra_script = os.environ.get('EXTRA_LANDMINES_SCRIPT')
+  if extra_script:
+    options.landmine_scripts.append(extra_script)

[iannucci, 2013/08/31 00:54:20]

I would put this above the apply_chromium_gyp_env. In fact, I would pull all the
argument parsing (including this) into its own function which just returns
landmine_scripts.

   for target in ('Debug', 'Release', 'Debug_x64', 'Release_x64'):
     landmines = []
     for s in options.landmine_scripts:
       proc = subprocess.Popen([sys.executable, s, '-t', target],
                               stdout=subprocess.PIPE)
       output, _ = proc.communicate()
       landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
+
     set_up_landmines(target, landmines)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())