iOS 9 Mail Question

After watching this video (below), I'm curious to know if you can add attachments from locations other than iCloud drive



The reason I ask is because in the video (skip to 3 min, 36 sec), when he presses and holds on a new mail message and opens up iCloud Drive, in the upper left hand corner of the screen, there is an option for "Locations". If Dropbox, Google Drive or OneDrive can be added as a "location", I am SOLD. I honestly hate the fact that when I want to share something from dropbox, I have to provide the URL to dropbox vs. just inserting the actual file into a new email. It is irritating, outdated and not necessary.