This is happening on my installation as well. After some light debugging I reached the same conclusions on this thread. It has to do with extensions as running with --disable-extensions doesn't cause it to crash. But, more interestingly, if you close the browser running without extensions and start chromium again as normal it works just fine for a while. But when it crashes it will not start cleanly again until it is run without extensions again at least once.
If I disable the native gnome extension (from package chrome-gnome-shell) the crash still occurs. Trying to rule out if there is any other particular extension I have installed that is causing the issue (have 2 or 3 more). Thanks for all your work. Toote