Clear All button added in  Recent Panelview.

Ref: https://github.com/temasek/android_frameworks_base/commit/a129580ee886b48c124de716236c2bae2b93a77b

Change-Id: I3547ec5bad197229f6d466e07099cdf9a321c092

Conflicts:
	services/java/com/android/server/power/ShutdownThread.java