During upgrade to the Chromium 61 we have switched from GTK2 to GTK3
and now we have a few warnings about stuff being deprecated in GTK3.
Check any Linux build to get a list of them.

/cc @zcbenz 
atom/browser/ui/message_box_gtk.cc
if (Browser::Get()->is_ready()) {
    GtkMessageBox(nullptr, MESSAGE_BOX_TYPE_ERROR, {"OK"}, -1, 0, "Error",
                  base::UTF16ToUTF8(title).c_str(),
                  base::UTF16ToUTF8(content).c_str(), "", false,
                  gfx::ImageSkia())
        .RunSynchronous();
  } else {
    fprintf(stderr,
            ANSI_TEXT_BOLD ANSI_BACKGROUND_GRAY
            ANSI_FOREGROUND_RED  "%s\n"
            ANSI_FOREGROUND_BLACK "%s"
            ANSI_RESET "\n",
            base::UTF16ToUTF8(title).c_str(),
            base::UTF16ToUTF8(content).c_str());
  }
}
}