[filesapp] Re-enable openQuickView PDF integration tests on MSAN

The MimeHandlerViewInCrossProcessFrame feature has shipped in ChromeOS
and the QuickView PDF tests should no longer crash on the MSAN bots as
a result. Re-enable these tests on MSAN.

Tbr: slangley
Bug: 768070
Change-Id: I77d195ffec0ea620c8681d3c3dc64406832b7674
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1933834
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#718525}
1 file changed