Revert "InCallUI: Store dialpad showing state (2/2)"

This reverts commit 77e2e31559d7e6be3f2f0944b3e8cba0f0b7bc28.

Change-Id: I822d084bec49054362d0af09fa18717eaf996c26
InCallUI: Heads up meets SlimKat....SlimKat meets Google IO [2/4]

Add native heads up support on dialer.

We only have show call in background feature. We combine it now with heads up.
So it is doing exactly same like on Google IO was shown.

Enabled by default.

- Notification is expanded by default
- Send as requested to force show the heads up no matter what.

Change-Id: I819316226f990058e6da6c289b8424d80ac1456e