int getNumReportedRegions(TableName table, QuotaSnapshotStore<TableName> tableStore)
      throws IOException {
      return Iterables.size(tableStore.filterBySubject(table));
    }
Computes the number of regions reported for a table.
hbase-server/src/main/java/org/apache/hadoop/hbase/quotas/QuotaObserverChore.java