Update from https://crrev.com/302630

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 the first hook (See DEPS). If it detects that
 the build should be clobbered, it will delete the contents of the build
 directory.
 
@@ skipping 25 matching lines @@
     r'c:\b\build\slave\win\build\src\out'
     '/mnt/data/b/build/slave/linux/build/src/out'
     '/b/build/slave/ios_rel_device/build/src/xcodebuild'
 
   Keep this function in sync with tools/build/scripts/slave/compile.py
   """
   ret = None
   if build_tool == 'xcode':
     ret = os.path.join(SRC_DIR, 'xcodebuild')
   elif build_tool in ['make', 'ninja', 'ninja-ios']:  # TODO: Remove ninja-ios.
-    ret = os.path.join(SRC_DIR, os.environ.get('CHROMIUM_OUT_DIR', 'out'))
+    if ('CHROMIUM_OUT_DIR' not in os.environ and
+        'output_dir' in landmine_utils.gyp_generator_flags()):
+      output_dir = landmine_utils.gyp_generator_flags()['output_dir']
+    else:
+      output_dir = os.environ.get('CHROMIUM_OUT_DIR', 'out')
+    ret = os.path.join(SRC_DIR, output_dir)
   else:
     raise NotImplementedError('Unexpected GYP_GENERATORS (%s)' % build_tool)
   return os.path.abspath(ret)
 
 
 def clobber_if_necessary(new_landmines):
   """Does the work of setting, planting, and triggering landmines."""
   out_dir = get_build_dir(landmine_utils.builder())
   landmines_path = os.path.normpath(os.path.join(out_dir, '..', '.landmines'))
   try:
@@ skipping 69 matching lines @@
     proc = subprocess.Popen([sys.executable, s], stdout=subprocess.PIPE)
     output, _ = proc.communicate()
     landmines.extend([('%s\n' % l.strip()) for l in output.splitlines()])
   clobber_if_necessary(landmines)
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main())