2ac555fe47
Note that this has little impact on current master - yet it allows to fix the 'Image Editor' bug (open image in editor, use same image in texture, delete image from texture, image us is 0 and red in image editor...) and probably a few other similar cases. But that change is mandatory to get a proper handling of ID deletion/reamapping/reloading/etc. as done in id-remap branch. Instead of just adding a user if none already present, new code use two new ID tags to get a three-states status: - Normal: nothing changes. - Needs extra user: we know that ID needs an extra user, so we take of never going down to 0 in 'real' usercount handling. - Has extra user: we do have increased that ID usercount to get our needed extrauser. Reviewers: sergey, campbellbarton Differential Revision: https://developer.blender.org/D1696