Enable correction/deleting notification via EasyEditSpan.

When the "delete" pop-up is clicked (and the wrapped text removed), the
creator of the span will receive a notification of the action.

Similarly, if the user modifies (i.e., add/remove a char), the creator of
the span will receive a notification too. The notification will not contain any
information about how the text has been modified.


Bug: 6905960
Change-Id: Ic227b8fd50066699915f69a54f225fb5330867c4