Ringer: Rewrite flashlight blink on incoming calls

* Stop using deprecated AsyncTask, use a HandlerThread & Looper instead
* Properly sync start and stop around mLock so it never keeps blinking
* Other misc improvements

Change-Id: I752ffa5d6629ad885c410fd1bfc3194b4bcc925b
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
Signed-off-by: Jis G Jacob <studiokeys@blissroms.org>
1 file changed