Chrome Version: 58.0.3007.0 (Official Build) dev (64-bit)
OS: ChromeOS

What steps will reproduce the problem?
I had several windows open, each with a pretty large number of tabs.
This was my first sign-in since rebooting the system to update, so a large swathe of my tabs were sharing a single process.

What happens instead?

Chrome started to jank, and when I checked Task Manager I saw the Browser process memory usage rising at ~10-20MB per second. Things broke down at about 3.6GB (my system has 4GB physical memory), at which point the GPU process started flaking out.

Shortly thereafter the system, surprisingly, recovered, to show my windows with most of the tabs dead and a load of extension-crashed notifications, with the Browser process consuming only 350MB. None of the tabs, nor any new tab, nor any extension, could be re-loaded, though.

I doubt that there is much we can do to diagnose this issue, since the system didn't actually crash and I of course couldn't get anything off it after it "recovered" - as part of the memory-infra work going on, though, ideally we should be able to hit a button to take a one-off memory trace and upload it and save it, in the hope of catching something useful in situations like this.