Cleanup using AndroidStudio code analyzer.

Moved to iterator for loops for ChartView and ChartFragment.

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

@@ -298,16 +298,6 @@ public class ChartFragment extends Fragment implements TrackDataListener {
         return trackDataHub != null && trackDataHub.isSelectedTrackRecording();
     }
 
-    /**
-     * Reloads the trackDataHub.
-     * Needs to be synchronized because trackDataHub can be accessed by multiple threads.
-     */
-    private synchronized void reloadTrackDataHub() {
-        if (trackDataHub != null) {
-            trackDataHub.reloadDataForListener(this);
-        }
-    }
-
     /**
      * Runs a runnable on the UI thread if possible.
      *