Add Overlay mode to the PorterDuff list of supported modes.
Add Overlay mode to the PorterDuff list of supported modes.

Change-Id: I2ec03b9a1039db3e3c16786222e4fde4782ed67e

xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base,xorware/android_frameworks_base