code: private void pruneExcessiveHistoricalRecordsIfNeeded() {
          final int pruneCount = mHistoricalRecords.size() - mHistoryMaxSize;
          if (pruneCount <= 0) {
              return;
          }
          mHistoricalRecordsChanged = true;
          for (int i = 0; i < pruneCount; i++) {
              HistoricalRecord prunedRecord = mHistoricalRecords.remove(0);
              if (DEBUG) {
                  Log.i(LOG_TAG, "Pruned: " + prunedRecord);
              }
          }
      }
docs: Prunes older excessive records to guarantee maxHistorySize.