Currently pressing alt focuses Chrome's menu button but only after releasing. The shortcut key tips can appear between pressing and releasing alt.

I'm lukewarm on this. I think the major argument against is that accesskeys have their share of other problems, like different modifier keys on different platforms, poor interaction with browser shortcuts, etc.

If we wanted to do something like this, I'd maybe start by adding it to Chrome's own UI, adding visual overlays for shortcuts in the toolbar, etc.

Either way, we'd probably want to go through UI review for this and evaluate how many top sites this would affect, plus figure out how it should work when the modifier key combination is something like Alt+Shift.