Reopen closed pane items in workspace – by uri instead of deserializing

[nathansobo]

Serializing and deserializing closed pane items was turning into a pain
with the new telepath changes that are phasing out this kind of on the
fly serialization. Reopening by uri saves memory and simplifies panes
enormously. If we want non-uri reopening we can revisit it later when
telepath models are better integrated.

[kevinsawicki]

Just curious, how does it save memory? 🐎

[benogle]

What are the implications of this? Say I have a bookmark on a buffer, on reload, will that marker still be there?

[nathansobo]

@kevinsawicki We are holding on to the serialized state of every destroyed item. In the previous world, this was just a blob of JSON but now that serialize returns orphaned documents, we end up potentially holding on to more. I was witnessing a memory leak on master that I'm pretty sure was due to this.

@benogle The marker isn't saved right now anyway. Markers are in buffers, and as soon as the editor is destroyed we destroy its markers. Someday we can serialize the markers outside the buffer, but without the ability to understand how the buffer has changed since the editor was last opened, this isn't actually that useful.