Simplify TrackDataHub interface.

src/main/java/de/dennisguse/opentracks/content/TrackDataHub.java

@@ -402,11 +402,7 @@ public class TrackDataHub {
             lastSeenTrackPointId = localLastSeenTrackPointIdId;
         }
 
-        if (trackPoint != null) {
-            for (TrackDataListener listener : sampledInListeners) {
-                listener.onNewTrackPointsDone(trackPoint, trackStatisticsUpdater.getTrackStatistics());
-            }
-        }
+        sampledInListeners.stream().forEach(TrackDataListener::onNewTrackPointsDone);
     }
 
     private void correctAltitude(TrackPoint trackPoint) {

src/main/java/de/dennisguse/opentracks/content/TrackDataListener.java

@@ -62,26 +62,28 @@ public interface TrackDataListener {
 
     /**
      * Called when finish sending new track points.
-     * This gets called after every batch of calls to {@link #onSampledInTrackPoint(TrackPoint, TrackStatistics, Speed, double)} and {@link #onSampledOutTrackPoint(TrackPoint, TrackStatistics)}.
      */
-    default void onNewTrackPointsDone(@NonNull TrackPoint lastTrackPoint, @NonNull TrackStatistics trackStatistics) {
+    default void onNewTrackPointsDone() {
     }
 
     /**
      * Called to clear previously sent markers.
      */
-    void clearMarkers();
+    default void clearMarkers() {
+    }
 
     /**
      * Called when a new marker is read.
      *
      * @param marker the marker
      */
-    void onNewMarker(Marker marker);
+    default void onNewMarker(Marker marker) {
+    }
 
     /**
      * Called when finish sending new markers.
      * This gets called after every batch of calls to {@link #clearMarkers()} and {@link #onNewMarker(Marker)}.
      */
-    void onNewMarkersDone();
+    default void onNewMarkersDone() {
+    }
 }

src/main/java/de/dennisguse/opentracks/fragments/ChartFragment.java

@@ -235,7 +235,7 @@ public class ChartFragment extends Fragment implements TrackDataListener {
     }
 
     @Override
-    public void onNewTrackPointsDone(@NonNull TrackPoint unused, @NonNull TrackStatistics alsoUnused) {
+    public void onNewTrackPointsDone() {
         if (isResumed()) {
             chartView.addChartPoints(pendingPoints);
             pendingPoints.clear();

src/main/java/de/dennisguse/opentracks/fragments/IntervalsFragment.java

@@ -24,7 +24,6 @@ import de.dennisguse.opentracks.TrackActivityDataHubInterface;
 import de.dennisguse.opentracks.adapters.IntervalStatisticsAdapter;
 import de.dennisguse.opentracks.content.TrackDataHub;
 import de.dennisguse.opentracks.content.TrackDataListener;
-import de.dennisguse.opentracks.content.data.Marker;
 import de.dennisguse.opentracks.content.data.Speed;
 import de.dennisguse.opentracks.content.data.Track;
 import de.dennisguse.opentracks.content.data.TrackPoint;
@@ -245,27 +244,12 @@ public class IntervalsFragment extends Fragment implements TrackDataListener {
     }
 
     @Override
-    public void onNewTrackPointsDone(@NonNull TrackPoint unused, @NonNull TrackStatistics alsoUnused) {
+    public void onNewTrackPointsDone() {
         if (isResumed()) {
             runOnUiThread(viewModel::onNewTrackPoints);
         }
     }
 
-    @Override
-    public void clearMarkers() {
-        // We don't care.
-    }
-
-    @Override
-    public void onNewMarker(Marker marker) {
-        // We don't care.
-    }
-
-    @Override
-    public void onNewMarkersDone() {
-        // We don't care.
-    }
-
     /**
      * Runs a runnable on the UI thread.
      *