If a `TextEditor` is recreated after a reframe and it has composition,
the composition including selection will be restored in the new
`TextEditor` instance as the same as the previous selection. Therefore,
restoring `Selection` should be treated as selection changes caused by
handling composition.
If selection is intentionally modified during a reframe, this change
could cause a regression. However, when the selection is changed, we
may ignore that with preserving the composition. However, it's hard
to avoid the situation and such web app is anyway not useful for IME
users. Therefore, we could try to take this fix until we would fix
bug 2017201.
Differential Revision: https://phabricator.services.mozilla.com/D312030
Masayuki Nakano
7c938433d2