@Override
  public void updateCompactionInputFileCount(boolean isMajor, long c) {
    compactionInputFileCountHisto.add(c);
    if (isMajor) {
      majorCompactionInputFileCountHisto.add(c);
    }
  }
Hadoop2 implementation of MetricsRegionServerSource. Implements BaseSource through
BaseSourceImpl, following the pattern
hbase-hadoop-compat/src/main/java/org/apache/hadoop/hbase/regionserver/MetricsRegionServerSourceImpl.java