Add documentation about clearing usage stats
Add documentation about clearing usage stats

Bug 5475575

Change-Id: Idee771a6b29dcd4870090cd1b5c72e126886fb47

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