This is the frameworks/base part of the fix for Bug 2158434: add a new
callback to the OnDialTriggerListener interface, so the RotarySelector can
tell the app about state changes between NOTHING_GRABBED and
LEFT_HANDLE_GRABBED and RIGHT_HANDLE_GRABBED.
BUG=2158434
DRNO=timsullivan
TESTED=regular incoming calls, call waiting calls, answering a call,
rejecting a call. Also verified I didn't affect the
lock screen at all.
88e037577f