[Picture-in-Picture] Enable if no GPU compositing.

This reverts https://chromium-review.googlesource.com/1042290 since
cc::Surfaces for video are now allowed to work with software
compositing.

Bug: 806249, 807840
Change-Id: Ie02c69d527b8e13235d744d3c2e98ea5b073f61d
Reviewed-on: https://chromium-review.googlesource.com/1062745
Reviewed-by: Jochen Eisinger <jochen@chromium.org>
Commit-Queue: Fran├žois Beaufort <beaufort.francois@gmail.com>
Cr-Commit-Position: refs/heads/master@{#559470}
1 file changed