[ MimeHandlerView ] Adapt more tests to MHVICPF

This CL makes some more tests pass with MHVICPF. Essentially,

  * BrowserPlugin tests return early as they expect a BrowserPlugin and
  with MHVCICPF we do not create one.
  * PDFExtensionInternal* tests are changed to use direct input routing
  to the guest WebContents when the flag is on.
  * PDFExtensionTest.EmbeddedPdfGetFocus will early return when MHVICPF
  is present (this is also a BrowserPlugin related test).

Bug: 961786
Change-Id: Ib90ee540283f23dccba1b7f8abfb4ee28e06654f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1611855
Reviewed-by: James MacLean <wjmaclean@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Ehsan Karamad <ekaramad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#660011}
2 files changed