This makes all inline allocation constructions go through the existing
{AllocationBuilder} helper class. It hence ensures there is a single
place for all sanity checking and and makes use-sites easier to read.

R=jarin@chromium.org

Change-Id: Ib5daf48acd93c631fccdfa095eda1afda7048115
Reviewed-on: https://chromium-review.googlesource.com/709056
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48502}