Add a platform version of VisibilityStore.

Integrates all the logic from ag/13312040 that was submitted upstream in
androidx-platform-dev. Since ag/13373289 will make the localstorage
VisibilityStore a no-op upstream, the logic will now live in platform
itself.

Bug: 169883602
Test: presubmit
Change-Id: Ice433f27cf585c1a3c4dce6c7a57bbbdddb2a821