LibOverride: Add a dedicated view in the Outliner.

This is a minimal, information-only view currently, listing by default
all the override data-blocks, with their user-edited override
properties.

System-generated overrides (like the overrides of pointers to other
override data-blocks) can be shown through a filter option.

Finally, potential info or warning messages from (auto-)resync propcess
are also shown, as an icon + tooltip next to the affected items.

Part of D10855.

1 files changed, 18 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/tree/tree_display.hh b/source/blender/editors/space_outliner/tree/tree_display.hh
index b6183050e82..f089a149805 100644
--- a/source/blender/editors/space_outliner/tree/tree_display.hh
+++ b/source/blender/editors/space_outliner/tree/tree_display.hh
@@ -111,6 +111,24 @@ class TreeDisplayLibraries final : public AbstractTreeDisplay {
 };
 
 /* -------------------------------------------------------------------- */
+/* Library Overrides Tree-Display. */
+
+/**
+ * \brief Tree-Display for the Library Overrides display mode.
+ */
+class TreeDisplayOverrideLibrary final : public AbstractTreeDisplay {
+ public:
+  TreeDisplayOverrideLibrary(SpaceOutliner &space_outliner);
+
+  ListBase buildTree(const TreeSourceData &source_data) override;
+
+ private:
+  TreeElement *add_library_contents(Main &, ListBase &, Library *) const;
+  bool override_library_id_filter_poll(Library *lib, ID *id) const;
+  short id_filter_get() const;
+};
+
+/* -------------------------------------------------------------------- */
 /* Video Sequencer Tree-Display */
 
 enum SequenceAddOp {