Fix an overflow found by ASAN.

Sometimes len is 0.

Change-Id: I031000188edc57663a5519b00cbbb751600d32f4
Implement Dynamic System Bars [1/2]

This commit implements DSB. Simple as that.

All the changes:
- frameworks/base (I3bc7102b2139fd1fa3de22aac096bd2a75bde878)
- packages/apps/Settings (Id2b105dfb3faf3cad74d0fa0dc33d01f6b71a853)

Change-Id: I3bc7102b2139fd1fa3de22aac096bd2a75bde878

Conflicts:
	core/java/android/provider/Settings.java
	packages/SystemUI/res/layout/status_bar.xml
	packages/SystemUI/res/values/config.xml
	packages/SystemUI/src/com/android/systemui/BatteryCircleMeterView.java
	packages/SystemUI/src/com/android/systemui/BatteryMeterView.java
	packages/SystemUI/src/com/android/systemui/statusbar/SignalClusterView.java
	packages/SystemUI/src/com/android/systemui/statusbar/StatusBarIconView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/BarTransitions.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarTransitions.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarView.java
	packages/SystemUI/src/com/android/systemui/statusbar/phone/PhoneStatusBarTransitions.java