Add file list combobox to diff editor

Change-Id: I2a40207ed3c4a5c07ba544d681aed6649a0b1a11
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/diffeditor/diffeditorplugin.h

@@ -66,7 +66,6 @@ private slots:
     void diff();
 
 private:
-    DiffEditorWidget *getDiffEditorWidget(const Core::IEditor *editor) const;
     QString getFileContents(const QString &fileName, QTextCodec *codec) const;
 
 };