Frameworks: Incoming Call in Background (3/3)

Patch ported from 4.2 which was done by our lovely HCP. A
very popular one so we bring it back and adapt it to 4.4

Allows user to set that Incoming Call UI will remain in background
if screen is on. Instead, a notification is added to StatusBar, which
can be used to bring up the Incoming Call UI. Ringtone and vibration
still occur as per system settings.

This has the same effect as apps marked as "immersive". It prevents
the incoming call from backgrounding the current activity.

Change-Id: I1eb0ae6b10ba02c3f1df95265d26a6c61db74aab

Conflicts:
	core/java/android/provider/Settings.java
GlobalActions: Fix Airplane Mode on/off issue

Issue: Unable to turn off Airplane mode from power button
       after phone reboot

Fix: Initialize mHasTelephony before the PhoneStateListener is
     registered to the TelephonyManager so that correct value
     of mHasTelephony is reflected when onServiceStateChanged
     callback is called.

https://android.googlesource.com/platform/frameworks/base/+/c3b7e6fd44593c3974e989d8ccf2097b4471b2b7

Bug: 13697360
Change-Id: Ide8afd9c16ea90b98b5912dbff440c5fd67b178d
Signed-off-by: houst0nn <houstonn@gmail.com>
Merge "Frameworks: Incoming Call in Background (3/3)" into kitkat
Merge "GlobalActions: Fix Airplane Mode on/off issue" into kitkat