Please make sure you're talking to UX before adding any new accelerators.

I think that these are Linux-only accelerators that we implemented to match GTK+. If they aren't the same on Windows and macOS, I don't think we want to implement them on Chrome OS.

Note that I'm not disagreeing that it'd be useful to have accelerators for reordering tabs (I use these all the time myself on Linux), but if they're added, they need to make sense for the platform. These seem like a bad choice for multiple reasons:

- They'll conflict with web pages that want these accelerators for themselves.
- They're extremely difficult to type on Chromebooks due to the lack of Page Up and Page Down keys (e.g. Ctrl+Shift+Search+Up).

I'm with derat on this one. I'm cool with adding the keys, but those particular combos are problematic.

When this last came up, the consensus from UI Reviwe was that we shouldn't add it:
https://groups.google.com/a/google.com/d/msg/chrome-ui-review/YhygnLNVR2I/EvA7d_r7AQAJ

Also it looks like this  may be a dup of  Issue 516834