Merge "Handle stub volumes in StorageSessionController" am: 6341816b31 am: ac9948da15

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1536702

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I1d6a220be5413fe6e1222acc753c6e8237e12a21