Add javadoc comments explaining SYNC_EXTRAS that did not have documentation
Add javadoc comments explaining SYNC_EXTRAS that did not have documentation

Change-Id: I3500f03076694fe5981fd5ec82e7f29062dfec53

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