Revert removal to allow Bookmark tabs as Folders to work

This reverts d0ae598348 which was
mistakenly removed.

src/BookmarkHandler.cpp

@@ -144,6 +144,19 @@ QString BookmarkHandler::iconForView(ViewProperties *view) const
     return {};
 }
 
+QList<KBookmarkOwner::FutureBookmark> BookmarkHandler::currentBookmarkList() const
+{
+    QList<KBookmarkOwner::FutureBookmark> list;
+    list.reserve(_views.size());
+
+    const QList<ViewProperties *> views = _views;
+    for (ViewProperties* view : views) {
+        list << KBookmarkOwner::FutureBookmark(titleForView(view), urlForView(view), iconForView(view));
+    }
+
+    return list;
+}
+
 bool BookmarkHandler::supportsTabs() const
 {
     return true;

src/BookmarkHandler.h

@@ -69,6 +69,7 @@ public:
     QString currentIcon() const override;
     bool enableOption(BookmarkOption option) const override;
     bool supportsTabs() const override;
+    QList<KBookmarkOwner::FutureBookmark> currentBookmarkList() const override;
     void openFolderinTabs(const KBookmarkGroup &group) override;
 
     /**