Consider desktop capture sessions in output protection checks.

BUG=325530
TEST=desktopCapture example.

Review URL: https://codereview.chromium.org/100863003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239328 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239328