Use ScopedTaskEnvironment instead of MessageLoop in /ppapi

MessageLoop will go away, eventually.

ScopedTaskEnvironment will per default start a ThreadPool, which should
be fine in most of the cases. If you belive your test needs to make sure
that no ThreadPool runs let me know and I will update the patch.

This CL was uploaded by git cl split.

Change-Id: Ib494b6fb9c77e44fa27c9afb2b98c4f0b775b892
Auto-Submit: Carlos Caballero <>
Reviewed-by: Raymes Khoury <>
Commit-Queue: Carlos Caballero <>
Cr-Original-Commit-Position: refs/heads/master@{#667946}
Cr-Mirrored-Commit: 7de7f44fdd1e1782744948daeeaae22f35fe439f
4 files changed