private void reportRegionStateTransition(ReportRegionStateTransitionResponse.Builder builder,
    ServerStateNode serverNode, List<RegionStateTransition> transitionList) throws IOException {
    for (RegionStateTransition transition : transitionList) {
      switch (transition.getTransitionCode()) {
        case OPENED:
        case FAILED_OPEN:
        case CLOSED:
          assert transition.getRegionInfoCount() == 1 : transition;
          final RegionInfo hri = ProtobufUtil.toRegionInfo(transition.getRegionInfo(0));
          long procId =
            transition.getProcIdCount() > 0 ? transition.getProcId(0) : Procedure.NO_PROC_ID;
          updateRegionTransition(serverNode, transition.getTransitionCode(), hri,
            transition.hasOpenSeqNum() ? transition.getOpenSeqNum() : HConstants.NO_SEQNUM, procId);
          break;
        case READY_TO_SPLIT:
        case SPLIT:
        case SPLIT_REVERTED:
          assert transition.getRegionInfoCount() == 3 : transition;
          final RegionInfo parent = ProtobufUtil.toRegionInfo(transition.getRegionInfo(0));
          final RegionInfo splitA = ProtobufUtil.toRegionInfo(transition.getRegionInfo(1));
          final RegionInfo splitB = ProtobufUtil.toRegionInfo(transition.getRegionInfo(2));
          updateRegionSplitTransition(serverNode, transition.getTransitionCode(), parent, splitA,
            splitB);
          break;
        case READY_TO_MERGE:
        case MERGED:
        case MERGE_REVERTED:
          assert transition.getRegionInfoCount() == 3 : transition;
          final RegionInfo merged = ProtobufUtil.toRegionInfo(transition.getRegionInfo(0));
          final RegionInfo mergeA = ProtobufUtil.toRegionInfo(transition.getRegionInfo(1));
          final RegionInfo mergeB = ProtobufUtil.toRegionInfo(transition.getRegionInfo(2));
          updateRegionMergeTransition(serverNode, transition.getTransitionCode(), merged, mergeA,
            mergeB);
          break;
      }
    }
  }
Delete the region states. This is called by "DeleteTable"
hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java