As of 2018, Chrome OS devices run kernels 3.8 or higher, where /proc/breakme is deprecated in favor of lkdtm. 

From snanda@'s comment at https://groups.google.com/a/chromium.org/forum/#!topic/chromium-os-dev/oOXfwuaan8o: 

/proc/breakme allows various kernel crash mechanisms such as null pointer deference, deadlocks etc. to be tested on demand:
https://chromium.googlesource.com/chromiumos/third_party/kernel-next/+/f0aacd435cc9f0f7fcf8ebc3b84f5a719ace21d1%5E!/

One newer kernels this functionality has been replaced by lkdtm:
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-os-dev/ErhFvMfaLHg


Having the references around is confusing for newbies who are looking at the code for unrelated reasons (e.g. debugging a failing test
in suite:kernel_per-build_regression which is required for all test-lab devices). 

Seeing references in the following test files:
- platform_CrashStateful.py
- platform_TrackpadStressServer.py
- platform_AnomalyCollector.py
- platform_KernelErrorPaths (several control files)