DO NOT MERGE: Revert "DO NOT MERGE: Remove AppSearch from Android R."

This reverts commit c9c71167.

This revert is to avoid merge conflict when ag/11299431 is auto-merged
to master.

This change will again be reverted when ag/11299431 lands.

Bug: 150999716
Test: m

Change-Id: Ia0f7a0e0eb8cf6f6f4d0693de01777a8a750c769