Call PTOpenProvider to make sure that XPS works.

BUG=317027
TBR=noamsml

Review URL: https://codereview.chromium.org/169903003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251707 0039d316-1c4b-4281-b951-d872f2087c98
LKGR w/ DEPS up to revision 251707