Framework/base: Added synchronization block to avoid race condition

Fix for the synchronization issue leading to access of an array
Index out of bounds. Issue occurs due to race condition between
removing the activities of a crashed process from history stack
and resuming a separate activity.

Change-Id: I14bb5834e778c15b674248e46fe93b0ce9f37967
FW: HALO Toggle

Icons: @kroz

Allow the user to switch HALO state by using the toggle. Long pressing toggle will open HALO settings.

Conflicts:
	packages/SystemUI/res/values/strings.xml
	packages/SystemUI/res/values/strings_toggles.xml
	packages/SystemUI/src/com/android/systemui/statusbar/toggles/ToggleManager.java

Change-Id: I82a13b4b9ba1d39a1f6c554ffd7b7859121901bc