void showDiffForTwo(@NotNull Project project,
                      @NotNull FilePath filePath,
                      @NotNull VcsFileRevision revision1,
                      @NotNull VcsFileRevision revision2);
void showDiffForTwo(@NotNull Project project,
                      @NotNull FilePath filePath,
                      @NotNull VcsFileRevision revision1,
                      @NotNull VcsFileRevision revision2)