Add MockTestActivityUtil to sc-dev

Partial cherry-pick of I0d4234752f266be2931497a9167c6051831e3dda.

Merged-In: I0d4234752f266be2931497a9167c6051831e3dda
Bug: 204906124
Change-Id: I46849722c832ab1d06f230beb260779ba356bc5b
1 file changed