This lets us share objects (Textures/RBs/Surface) in the attachment class. It will let us squash the attachment classes into one type, which will in turn let us store them by-value, instead of by-pointer. BUG=angleproject:963 Change-Id: Ia9a43dbc3b99475c00f6bc2ed5475deef55addc3 Reviewed-on: https://chromium-review.googlesource.com/263487Reviewed-by: Kenneth Russell <kbr@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>
