[ MimeHandlerView ] Adapt ChromeAcceptHeaderTest to frame-based case

In frame-based MimeHandlerView, PDF in <embed> and <object> leads to a
navigation followed by creating a GuestView inside. This means the
renderer will not be sending a resource request.

Bug: 961786
Change-Id: I5224a61bcb80a854cabf706d7009cd2d1b9893db
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1615581
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660492}
1 file changed