Doesn't seem to be a meaningful bug report to triage this.

@reporter: Could you please confirm exact issue (with clear steps) you are facing on Chrome with the latest versions (stable-62.0.3202.89 & canary-64.0.3261.0) on which OS. Please follow this http://www.chromium.org/for-testers/bug-reporting-guidelines.
Thanks..!

tbansal@, I know this isn't a result of your change to networks_metrics_provider.  However, now that you're familiar with the code, can you please glance at it?  (After all, a NOTREACHED likely means the UMA logs are also going to be incorrect.)

Looks like the code is only active on Chrome OS.

So I filed the bug at the "explicit request" of the Google Log Analyzer (https://toolbox.googleapps.com/apps/loganalyzer/). That thing detected the NOTREACHED() condition in the ui log file, and said "this is always a bug, please report it". So I did.

I'm a volunteer "IT guy" at a local non-profit, so I actually don't know what the user may or may not have seen on the ChromeBook when this NOTREACHED() condition was hit. So I've no steps to reproduce, nor any symptom to point to. I can inquire of the user about errors or problems if that would help. If you all happen to have a few hints as to what conditions might result in this apparent error condition in the software, I could use that as guidance. Otherwise, you could close the bug report, and I'll file a new one if/when I have something more concrete.

Sorry if this all has caused some pointless work. I'm new to ChromeBooks and their errors (but not new to computers; been debugging them for 25 years now).

marcus.winston: Thanks for reporting the issue. You did the right thing.

Now the next steps are on us (Chrome team) to figure out what's the best solution. We're still discussing the right thing to do here, but hopefully we can find the right solution. Don't worry about that - since it's on our side now. And please do continue to report bugs in the future. :)