QmlProfiler: Load the timeline model data event by event

All the models do the same thing when loading the data: They iterate
the list of events, determine for each one if they accept it, and if
so, they load it. After the list has been fully loaded, they do some
finalization. This can be centralized, and ultimately we won't need to
expose the central QVector<QmlEvent> for that anymore.

Change-Id: Ia82facfdc3968200bbec323a02f2fcc02ac44e9e
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/qmlprofiler/debugmessagesmodel.h

@@ -34,9 +34,6 @@ class DebugMessagesModel : public QmlProfilerTimelineModel
 {
     Q_OBJECT
 
-protected:
-    bool accepted(const QmlEventType &event) const override;
-
 public:
     DebugMessagesModel(QmlProfilerModelManager *manager, QObject *parent = 0);
 
@@ -46,7 +43,8 @@ public:
     QVariantMap details(int index) const override;
     int expandedRow(int index) const override;
     int collapsedRow(int index) const override;
-    void loadData() override;
+    void loadEvent(const QmlEvent &event, const QmlEventType &type) override;
+    void finalize() override;
     void clear() override;
     QVariantMap location(int index) const override;