bug(linux): Chromium on Wayland sometimes deletes decomposed cluster on Backspace

[ermshiperete]

(This came out of testing #15550 and #15609)

Chrome/Chromium behaves as compliant app when running with Wayland.

Using the bksp_ldml.zip keyboard from #15550, type the sequence abc     d/, then press Bksp.

Note that both the d and the combining acute are deleted with a single keystroke, which is unexpected - only the combining acute should have been deleted.

If you switch to a different app and back before pressing Backspace things work as expected.

See also #15676.