gnome: clean up ringmainwindow.cpp

Define custom widgets in separate files and move
commonly used functions to utils:
- moved get_index_from_selection() to utils/models
- moved place_new_call() to utils/calling
- moved the contacts treeview to contactsview
- moved the history treeview to historyview

Refs #71530

Change-Id: Ia20e8d3bc3cfe997d38c880854205f063f0244a0
diff --git a/src/utils/models.h b/src/utils/models.h
new file mode 100644
index 0000000..e227f8f
--- /dev/null
+++ b/src/utils/models.h
@@ -0,0 +1,41 @@
+/*
+ *  Copyright (C) 2015 Savoir-Faire Linux Inc.
+ *  Author: Stepan Salenikovich <stepan.salenikovich@savoirfairelinux.com>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.
+ *
+ *  Additional permission under GNU GPL version 3 section 7:
+ *
+ *  If you modify this program, or any covered work, by linking or
+ *  combining it with the OpenSSL project's OpenSSL library (or a
+ *  modified version of that library), containing parts covered by the
+ *  terms of the OpenSSL or SSLeay licenses, Savoir-Faire Linux Inc.
+ *  grants you additional permission to convey the resulting work.
+ *  Corresponding Source for a non-source form of such a combination
+ *  shall include the source code for the parts of OpenSSL used as well
+ *  as that of the covered work.
+ */
+
+#ifndef _MODELS_H
+#define _MODELS_H
+
+#include <gtk/gtk.h>
+
+class QModelIndex;
+
+QModelIndex
+get_index_from_selection(GtkTreeSelection *selection);
+
+#endif /* _MODELS_H */
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