Synchronize increment of resource cache generations

Test: manual/presubmits
Fixes: 287691671
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c137aac4d8bbe2c7f36f2b5b60dc3bfa86bc0457)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:d58dcf55141d9bc72e40f45a3e735fb15dae7439)
Merged-In: I6189813291d3581fc401fd29801ae46c6eeab58c
Change-Id: I6189813291d3581fc401fd29801ae46c6eeab58c