Use post revisions as storage backend for post/postmeta changes #339
Description
There is currently a duplication of pending post data in the customizer vs the post editor. Pending changes made via the edit post screen get stored in a revision whereas the changes made via the customizer get embedded into a changeset. Ideally the pending changes in changesets should get exposed as autosave revisions post editor to continue editing. When editing a post in the customizer and you leave without publishing, those post changes are stored in a changeset. If you go to the editor, you will not see any reference to those changes. It would be helpful to users to list out the posts in pending changesets that they could “import” as an autosave revision to continue editing.
For that matter, should changesets not store the full post content in the changeset but always store it in such post revisions? The underlying setting value could be the ID of the revision, where the js_value then returns full hydrated content.