Before this change the ImBuf struct had dedicated fields for the
buffer data. Now the color space is stored inside of the struct
which wraps around the buffer information.
This only changes the field placement, without changing the way
it is handled. In the future one might imagine that operations
like stealing buffer data should null-ify the buffer colorspace
pointer. Such changes would need to have more accurate thinking
before implementation.
Should be no functional changes.
Pull Request: https://projects.blender.org/blender/blender/pulls/109291
d8cc8fcf7f