@NotNull
  @Override
  public ContentDiffRequest createFromFiles(@Nullable Project project, @Nullable VirtualFile file1, @Nullable VirtualFile file2) {
    assert file1 != null || file2 != null;

    DiffContent content1 = file1 != null ? myContentFactory.create(project, file1) : myContentFactory.createEmpty();
    DiffContent content2 = file2 != null ? myContentFactory.create(project, file2) : myContentFactory.createEmpty();

    String title1 = getContentTitle(file1);
    String title2 = getContentTitle(file2);

    String title = getTitle(file1, file2);

    return new SimpleDiffRequest(title, content1, content2, title1, title2);
  }
@NotNull
  @Override
  public ContentDiffRequest createFromFiles(@Nullable Project project, @Nullable VirtualFile file1, @Nullable VirtualFile file2)