Preload zip archiver NaCl module for zip browser tests.

In DEBUG builds, the PNaCl translation takes a significant amount of
time, causing zip browser test TIMEOUT flakes on the bots.

Recover the FilesApp browser test feature used to declare ZipTests and
for the zip browser tests, tell the zip-archiver extension to preload
the NaCl module before it's needed, so its translation starts as early
as possible during zip browser tests.

BUG=889703

Change-Id: Ic16a4b4e53a4be88bae8ee5d2c2caa8baaa1487b
Reviewed-on: https://chromium-review.googlesource.com/c/1257464
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Anand Mistry <amistry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#596470}
4 files changed