First failure:
https://ci.chromium.org/buildbot/chromium.chrome/Google%20Chrome%20Mac/33045

end of log:
WARNING: Couldn't match revinfo line:
src/chrome/test/data/firefox3_profile/searchplugins: None
WARNING: Couldn't match revinfo line:
src/chrome/test/data/firefox3_searchplugins: None
WARNING: Couldn't match revinfo line:
src/chrome/test/data/perf/frame_rate/private: None
WARNING: Couldn't match revinfo line:
src/data/autodiscovery: None
WARNING: Couldn't match revinfo line:
src/data/mach_ports: None
WARNING: Couldn't match revinfo line:
src/data/memory_test: None
WARNING: Couldn't match revinfo line:
src/data/mozilla_js_tests: None
WARNING: Couldn't match revinfo line:
src/data/page_cycler: None
WARNING: Couldn't match revinfo line:
src/data/selenium_core: None
WARNING: Couldn't match revinfo line:
src/data/tab_switching: None
WARNING: Couldn't match revinfo line:
src/webkit/data/bmp_decoder: None
WARNING: Couldn't match revinfo line:
src/webkit/data/ico_decoder: None
WARNING: Couldn't match revinfo line:
src/webkit/data/test_shell/plugins: None
Traceback (most recent call last):
  File "/b/rr/tmpqwoGX6/rw/checkout/scripts/slave/.recipe_deps/depot_tools/recipes/recipe_modules/bot_update/resources/bot_update.py", line 1293, in <module>
    sys.exit(main())
  File "/b/rr/tmpqwoGX6/rw/checkout/scripts/slave/.recipe_deps/depot_tools/recipes/recipe_modules/bot_update/resources/bot_update.py", line 1277, in main
    checkout(options, git_slns, specs, revisions, step_text, shallow)
  File "/b/rr/tmpqwoGX6/rw/checkout/scripts/slave/.recipe_deps/depot_tools/recipes/recipe_modules/bot_update/resources/bot_update.py", line 1231, in checkout
    gclient_output, options.patch_root, options.gerrit_ref))
  File "/b/rr/tmpqwoGX6/rw/checkout/scripts/slave/.recipe_deps/depot_tools/recipes/recipe_modules/bot_update/resources/bot_update.py", line 480, in create_manifest
    if not revision and len(url_split) == 2:
TypeError: object of type 'NoneType' has no len()
step returned non-zero exit code: 1

Bot has been failing for a while.