Tracing: CtfVisualizer: Apply thread restrictions to statistics, too

The statistics are now also filtered by the selected threads. If no
thread is selected, the statistics are presented for all threads combined.
This fixes a bug with double counted events, too.

Change-Id: I9afa0bf5bc85ccf363e00600e75001c0ab3f2e8a
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/ctfvisualizer/ctftracemanager.h

@@ -77,6 +77,8 @@ protected:
     void addModelForThread(int threadId, int processId);
     void addModelsToAggregator();
 
+    void updateStatistics();
+
     void clearAll();
 
     Timeline::TimelineModelAggregator *const m_modelAggregator;