void updateSpaceQuotaAfterFileReplacement(RegionSizeStore sizeStore, RegionInfo regionInfo,
    Collection<HStoreFile> oldFiles, Collection<HStoreFile> newFiles) {
    long delta = 0;
    if (oldFiles != null) {
      for (HStoreFile compactedFile : oldFiles) {
        if (compactedFile.isHFile()) {
          delta -= compactedFile.getReader().length();
        }
      }
    }
    if (newFiles != null) {
      for (HStoreFile newFile : newFiles) {
        if (newFile.isHFile()) {
          delta += newFile.getReader().length();
        }
      }
    }
    sizeStore.incrementRegionSize(regionInfo, delta);
  }
Updates the space quota usage for this region, removing the size for files compacted away and
adding in the size for new files.
@param sizeStore  The object tracking changes in region size for space quotas.
@param regionInfo The identifier for the region whose size is being updated.
@param oldFiles   Files removed from this store's region.
@param newFiles   Files added to this store's region.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HStore.java