Blender Git Loki

Fix T71908: Animated properties are lost after frame-post handler

The issue was caused by special handling of animation update after
manual edits in frame_post handler: to avid loss of manual edits
done on top of animated property. This was done as a separate pass
for non-animation update after frame_post did modifications.

This caused some other side-effect: non-modified animated property
was re-setting to the value which is used in the viewport.

Idea of this solution is simple: preserve values which came from
animation update through copy-on-write process. The actual process
of this is a bit involved: need to decode RNA path and do it twice
since f-curve might point to a sub-data which pointer will change.
Since this is only done for non-active depsgraph (aka depsgraph
used for render pipeline) this is probably fine since all this
extra overhead is just a fraction of overall render process.

Differential Revision: https://developer.blender.org/D6330