File "/b/c/b/Android_Release__Nexus_6_/irs86uzD/third_party/android_platform/development/scripts/stack", line 240, in <module>
    sys.exit(main(sys.argv[1:]))
  File "/b/c/b/Android_Release__Nexus_6_/irs86uzD/third_party/android_platform/development/scripts/stack", line 196, in main
    constants.CheckOutputDirectory()
  File "/b/c/b/Android_Release__Nexus_6_/irs86uzD/third_party/android_platform/development/scripts/../../../../build/android/pylib/constants/__init__.py", line 206, in CheckOutputDirectory
    'out dirs exist: %r' % dirs)
Exception: Neither CHROMIUM_OUTPUT_DIR nor CHROMIUM_OUT_DIR has been set. CHROME_HEADLESS detected, but multiple out dirs exist: []