@Nullable
    @Override
    protected ContentRevision getContentRevision() {
      final ItemLatestState itemState = myDiffProvider.getLastRevision(mySelectedFile);
      if (itemState == null) return null;

      myFileStillExists = itemState.isItemExists();
      return myDiffProvider.createFileContent(itemState.getNumber(), mySelectedFile);
    }
@Nullable
    @Override
    protected ContentRevision getContentRevision()