In PersistentValueMap, SetWeak function should supply WeakCallbackType arguments.

Cq-Include-Trybots: master.tryserver.chromium.linux:linux_chromium_rel_ng
Change-Id: I70a59e90b7ea0a10f695419e57ae9bfb8d5ba852
Reviewed-on: https://chromium-review.googlesource.com/684002
Commit-Queue: Marja Hölttä <marja@chromium.org>
Reviewed-by: Marja Hölttä <marja@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48529}