Pull upstream changes from AndroidX.

Changes included:
#287105e: Refactor SearchResultPage out of localstorage to its
          own class.
#c89cdd0: Delete LocalBackendSyncImpl.
#4ac0d9d: Create GlobalAppSearchManager for global query.
#87c01a9: Replace AppSearch removeByNamespace, removeBySchemaType
          and removeAll by removeByQuery.

Bug: 162450968,169883602,169275184
Test: builds
Change-Id: Ib2d442deacb7b066786e00a3eabf95955abd8403