[gnote] Add text_content() to NoteBase

[Aurimas Černius <aurimasc src gnome org>]

commit 85c09e8f6733dd33c975ee7abfdf9f377d65248a
Author: Aurimas Černius <aurisc4 gmail com>
Date:   Sat Jul 11 18:19:24 2020 +0300

    Add text_content() to NoteBase

 src/note.hpp     | 4 ++--
 src/notebase.cpp | 5 +++++
 src/notebase.hpp | 1 +
 3 files changed, 8 insertions(+), 2 deletions(-)
---
diff --git a/src/note.hpp b/src/note.hpp
index 491ded28..9b63a46a 100644
--- a/src/note.hpp
+++ b/src/note.hpp
@@ -1,7 +1,7 @@
 /*
  * gnote
  *
- * Copyright (C) 2011-2015,2017,2019 Aurimas Cernius
+ * Copyright (C) 2011-2015,2017,2019-2020 Aurimas Cernius
  * Copyright (C) 2009 Hubert Figuiere
  *
  * This program is free software: you can redistribute it and/or modify
@@ -120,7 +120,7 @@ public:
   virtual void set_title(const Glib::ustring & new_title, bool from_user_action) override;
   virtual void rename_without_link_update(const Glib::ustring & newTitle) override;
   virtual void set_xml_content(const Glib::ustring & xml) override;
-  Glib::ustring text_content();
+  virtual Glib::ustring text_content() override;
   void set_text_content(const Glib::ustring & text);
 
   const Glib::RefPtr<NoteTagTable> & get_tag_table();
diff --git a/src/notebase.cpp b/src/notebase.cpp
index e65f6805..8f5e64de 100644
--- a/src/notebase.cpp
+++ b/src/notebase.cpp
@@ -289,6 +289,11 @@ void NoteBase::set_xml_content(const Glib::ustring & xml)
   data_synchronizer().set_text(xml);
 }
 
+Glib::ustring NoteBase::text_content()
+{
+  return "";
+}
+
 void NoteBase::load_foreign_note_xml(const Glib::ustring & foreignNoteXml, ChangeType changeType)
 {
   if(foreignNoteXml.empty())
diff --git a/src/notebase.hpp b/src/notebase.hpp
index 5a733f8a..cb903df5 100644
--- a/src/notebase.hpp
+++ b/src/notebase.hpp
@@ -233,6 +233,7 @@ public:
       return data_synchronizer().text();
     }
   virtual void set_xml_content(const Glib::ustring & xml);
+  virtual Glib::ustring text_content();
   void load_foreign_note_xml(const Glib::ustring & foreignNoteXml, ChangeType changeType);
   std::vector<Tag::Ptr> get_tags() const;
   const NoteData & data() const;