Register implicit broadcasts at runtime for updating widgets

It resolves Broadcast Limitations issue if target API level is changed
as 26 or higher later.
It includes fixing code style also.

Test: Check messaging widgets' changes.

Change-Id: I6e08027b1d6a5a19cfd17f8ec3e9a895dbb3c44a
Signed-off-by: Taesu Lee <taesu82.lee@samsung.com>
2 files changed