This was put in so that we could roll back the backspace shortcut if something went wrong. I think enough time has passed that we can remove this now.

Ojan, can you do it?

https://cs.chromium.org/chromium/src/chrome/common/chrome_features.cc?q=BackspaceGoesBack&l=60

While doing that, please remove the sentence in chrome_command_ids.h that references this field trial.