Fix edge case for eviction
Fix edge case for eviction

If nothing is buffered, we should not treat this as a buffer from 0.

Change-Id: If691102f11d2efcb64964ae103d898217cd49dc7

Ross-cz/shaka-player,baconz/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,vimond/shaka-player,ustudio/shaka-player,indiereign/shaka-player,TheModMaker/shaka-player,indiereign/shaka-player,vimond/shaka-player,shaka-project/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,indiereign/shaka-player,russitto/shaka-player,baconz/shaka-player,brightcove/shaka-player,shaka-project/shaka-player,brightcove/shaka-player,TobbeEdgeware/shaka-player,vimond/shaka-player,ustudio/shaka-player,Ross-cz/shaka-player,baconz/shaka-player,TheModMaker/shaka-player,tvoli/shaka-player,brightcove/shaka-player,tvoli/shaka-player,russitto/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,TobbeEdgeware/shaka-player,russitto/shaka-player,Ross-cz/shaka-player,ustudio/shaka-player,ustudio/shaka-player,TobbeEdgeware/shaka-player