Factor out InstanceID token TTL logic away from gcl engine

This patch moves TTL logic (crrev.com/c/1950987) to FCMNetworkHandler
layer. There should be no behavioral changes.

Bug: 1034510
Change-Id: I324073677027065dd50b399351f24479d3d35579
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2038731
Commit-Queue: Maksim Moskvitin <[email protected]>
Reviewed-by: Peter Beverloo <[email protected]>
Reviewed-by: Marc Treib <[email protected]>
Cr-Commit-Position: refs/heads/master@{#738935}
31 files changed