Move export and remove buttons into the Panel header row

This reverts commit 82232196fe.

@@ -417,0 +433,4 @@
+
+  bke::FileHandlerType *fh = bke::file_handler_find(name);
+  if (!fh) {
+    return OPERATOR_CANCELLED;

@@ -417,0 +437,4 @@
+  }
+
+  if (!WM_operatortype_find(fh->export_operator, true)) {
+    return OPERATOR_CANCELLED;

@@ -417,0 +446,4 @@
+  STRNCPY(data->fh_idname, fh->idname);
+
+  IDPropertyTemplate val{};
+  data->export_properties = IDP_New(IDP_GROUP, &val, "io_wmOpItemProp");

@@ -417,0 +462,4 @@
+  /* identifiers */
+  ot->name = "Add Exporter";
+  ot->description = "Add Exporter";
+  ot->idname = "COLLECTION_OT_io_handler_add";

@@ -417,0 +466,4 @@
+
+  /* api callbacks */
+  ot->exec = collection_io_handler_add_exec;
+  ot->poll = WM_operator_winactive;

@@ -417,0 +501,4 @@
+  /* identifiers */
+  ot->name = "Remove Exporter";
+  ot->description = "Remove Exporter";
+  ot->idname = "COLLECTION_OT_io_handler_remove";

@@ -417,0 +505,4 @@
+
+  /* api callbacks */
+  ot->exec = collection_io_handler_remove_exec;
+  ot->poll = WM_operator_winactive;

@@ -417,0 +510,4 @@
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  RNA_def_int(ot->srna, "index", 0, 0, INT_MAX, "Index", "IO Handler index", 0, INT_MAX);

@@ -417,0 +568,4 @@
+  /* identifiers */
+  ot->name = "Export";
+  ot->description = "Invoke the export operation";
+  ot->idname = "COLLECTION_OT_io_handler_export";

@@ -417,0 +572,4 @@
+
+  /* api callbacks */
+  ot->exec = collection_io_handler_export_exec;
+  ot->poll = WM_operator_winactive;

@@ -417,0 +577,4 @@
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  RNA_def_int(ot->srna, "index", 0, 0, INT_MAX, "Index", "IO Handler index", 0, INT_MAX);

@@ -417,0 +605,4 @@
+  /* identifiers */
+  ot->name = "Export All";
+  ot->description = "Invoke all configured exporters on this collection";
+  ot->idname = "COLLECTION_OT_io_export_all";

@@ -417,0 +609,4 @@
+
+  /* api callbacks */
+  ot->exec = collection_io_export_all_exec;
+  ot->poll = WM_operator_winactive;

@@ -417,0 +651,4 @@
+
+  /* api callbacks */
+  ot->exec = wm_collection_export_all_exec;
+  ot->poll = WM_operator_winactive;

@@ -569,0 +571,4 @@
+  StructRNA *srna;
+  PropertyRNA *prop;
+
+  srna = RNA_def_struct(brna, "IOHandlerData", nullptr);

@@ -569,0 +580,4 @@
+  RNA_def_property_ui_text(prop, "Is Open", "Whether the panel is expanded or closed");
+  RNA_def_property_flag(prop, PROP_NO_DEG_UPDATE);
+  RNA_def_property_update(prop, NC_SPACE | ND_SPACE_PROPERTIES, nullptr);
+}

@@ -653,1 +669,4 @@
                            "Children collections their parent-collection-specific settings");
+
+  /* IO Handlers. */
+  prop = RNA_def_property(srna, "io_handlers", PROP_COLLECTION, PROP_NONE);

@@ -1222,2 +1222,4 @@
       child_layer->runtime_flag |= LAYER_COLLECTION_VISIBLE_VIEW_LAYER;
     }
+
+    if (!BLI_listbase_is_empty(&child_collection->exporters)) {

@@ -419,0 +465,4 @@
+  data->flag |= IO_HANDLER_PANEL_OPEN;
+
+  BLI_addtail(exporters, data);
+

@@ -419,0 +468,4 @@
+
+  WM_event_add_notifier(C, NC_SPACE | ND_SPACE_PROPERTIES, nullptr);
+  WM_event_add_notifier(C, NC_SPACE | ND_SPACE_OUTLINER, nullptr);
+  BKE_layer_collection_sync(CTX_data_scene(C), CTX_data_view_layer(C));

@@ -419,0 +503,4 @@
+
+  BKE_collection_exporter_free_data(data);
+
+  BLI_remlink(exporters, data);