SequenceBound: migrate from Post() to AsyncCall() in storage classes (take 2)

Bug: 1140588
Change-Id: I41cf5373408f5344e1a0b05870cf8da9c6442b40
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2680062


Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Joshua Bell <jsbell@chromium.org>
Auto-Submit: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Joshua Bell <jsbell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#851383}