Improve InCallUI fragment management

* Load some fragments on demand
  * ConferenceManagerFragment
  * DialpadFragment
* Remove ConferenceManagerFragment from incall_screen.xml so that
it is no longer loaded statically
* Add helper methods to InCallActivity to facilitate dynamically
loading fragments
* Fix some bugs with fragment visibility and activity recreation

Change-Id: I475e2302fae415817f06da209dd6484c89467480
10 files changed
tree: 5400938433726257765bb89a204bc47ff35734ec
  1. InCallUI/