[ MimeHandlerView ] Explicitly turn flag off in certain spp tests

Some of ChromeSitePerProcessPDFTests are actually BrowserPlugin-based
tests which do not make sense or fail with the frame-based
MimeHandlerView. This CL ensures the corresponding flag is turned off.

Bug: 961786
Change-Id: I388b417cf92661cff14f5b69d2ea0d74758ade9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614359
Reviewed-by: Ɓukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660276}
1 file changed