When we detect text being deleted from the URL bar via setComposingText while we're displaying an autocomplete suggestion, we clear the autocomplete text and prevent the keyboard's delete from having any effect on the URL bar by returning false.
Some keyboards might not handle this correctly and assume that they've in fact successfully set the new text, so the next time the user presses a key can lead to weird behaviour. As a workaround, we therefore additionally restart the input for affected keyboards.
MozReview-Commit-ID: DucveafL3AB
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extra : rebase_source : 3ba1701adf7e4e8a03d263a75c04717aadaab663
73b4249e96