Merge "DO NOT MERGE ANYWHERE: ImageReader: Add discardFreeBuffers method" into nyc-dev am: e93c655093  -s ours am: def3c209db  -s ours am: d28f5d5e5a  -s ours am: 3558072a43  -s ours
am: 17ff4378d8  -s ours

Change-Id: Ib8df679a1714359bc1fd1713a27c60f4e0947f4f