[automerger skipped] Merge "Add comments in grouping APIs to clarify possible...
[automerger skipped] Merge "Add comments in grouping APIs to clarify possible exceptions." am: 42adca41
am: 7aacd108 -s ours
am skip reason: change_id I3671e366be7e8c3a75b5ee23b7cf88a33ecd3a4f with SHA1 e00887f6 is in history
Change-Id: Ib4f1629b1072cc4af736a1c15a8d5faac72f0ce8