timeline: made ReplaceBlocksWithGaps more accessible for other parts of the program

app/widget/timelinewidget/timelinewidget.cpp

@@ -505,16 +505,11 @@ void TimelineWidget::DeleteSelected(bool ripple)
 {
   QList<TimelineViewBlockItem *> selected_list = GetSelectedBlocks();
   QList<Block*> blocks_to_delete;
-  QList<TrackReference> tracks_affected;
 
   foreach (TimelineViewBlockItem* item, selected_list) {
     Block* b = item->block();
 
     blocks_to_delete.append(b);
-
-    if (!tracks_affected.contains(item->Track())) {
-      tracks_affected.append(item->Track());
-    }
   }
 
   // No-op if nothing is selected

app/widget/timelinewidget/timelinewidget.h

@@ -103,6 +103,8 @@ public:
 
   void RestoreSplitterState(const QByteArray& state);
 
+  static void ReplaceBlocksWithGaps(const QList<Block *>& blocks, bool remove_from_graph, QUndoCommand* command);
+
 signals:
   void BlocksSelected(const QList<Block*>& selected_blocks);
 
@@ -460,8 +462,6 @@ private:
 
   void InsertGapsAt(const rational& time, const rational& length, QUndoCommand* command);
 
-  void ReplaceBlocksWithGaps(const QList<Block *>& blocks, bool remove_from_graph, QUndoCommand* command);
-
   void SetBlockLinksSelected(Block *block, bool selected);
 
   QVector<Timeline::EditToInfo> GetEditToInfo(const rational &playhead_time, Timeline::MovementMode mode);