Clear the selection when hiding the handles

Bug: 18200283

Cherry-pick https://codereview.chromium.org/713493003.

Clear the selected text when hiding the handles and the desired
behavior is to "unselect all on dismiss".

BUG=430859
internal b/18200283

Review URL: https://codereview.chromium.org/713493003

Change-Id: Ie8d751774c6341054f0c1b8d4cca91ba6877e373
Cr-Commit-Position: refs/heads/master@{#303946}
1 file changed