[1/2] InCall: Add a non-intrusive dialog for incoming calls

Change-Id: I7c8b5cc5138a5543be30579e99bd9989624e2abe
(cherry picked from commit 22f87dd1e31db5cf6c2a112e53f79844db4f5865)
[3/3] InCallUI: allow disabling non intrusive incall ui

Change-Id: I86bd4b46f031004fa90f1d7936263f9dabcd3860

Patchset: 3
https://gerrit.omnirom.org/#/c/3049/
(cherry picked from commit 040330c8a3c8be23931761d6efc0435f19c42666)