SystemUI: fix calculating alpha for back button in landscape mode.

Change-Id: Iea7a2eed86d4b65d3772b95f613d1853c66a0158

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarTransitions.java
Fix ellipsizing of emoji symbols in StatisLayout.

Change-Id: Ia057053a7dd6e5a256499f6bded99872581de18e