It is exactly the same experience as user right-click and
select "SaveAs..." from pop-up menu. No disk access allowed for plugin.

DIscussed it with Chris Evans and he is ok with this solution from the security stand point.

Also added PDF resources for new UI.

BUG=56072,75235
TEST=none, will send PDF cl separately.
Review URL: http://codereview.chromium.org/6871020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@81822 0039d316-1c4b-4281-b951-d872f2087c98