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
GtkIconSource* iconsource = gtk_icon_source_new();
      GtkIconSet* iconset = gtk_icon_set_new();
      gtk_icon_source_set_pixbuf(iconsource, pixbuf);
      gtk_icon_set_add_source(iconset, iconsource);
      GtkWidget* image = gtk_image_new_from_icon_set(iconset,
                                                     GTK_ICON_SIZE_DIALOG);
      gtk_message_dialog_set_image(GTK_MESSAGE_DIALOG(dialog_), image);
      gtk_widget_show(image);
      gtk_icon_source_free(iconsource);
      gtk_icon_set_unref(iconset);
      g_object_unref(pixbuf);
    }
    if (!checkbox_label.empty()) {
      GtkWidget* message_area =
          gtk_message_dialog_get_message_area(GTK_MESSAGE_DIALOG(dialog_));
      GtkWidget* check_button =
          gtk_check_button_new_with_label(checkbox_label.c_str());
      g_signal_connect(check_button, "toggled",
                       G_CALLBACK(OnCheckboxToggledThunk), this);
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(check_button),
                                   checkbox_checked);
      gtk_container_add(GTK_CONTAINER(message_area), check_button);
    }
    
    for (size_t i = 0; i < buttons.size(); ++i) {
      GtkWidget* button = gtk_dialog_add_button(
          GTK_DIALOG(dialog_), TranslateToStock(i, buttons[i]), i);
      if (static_cast<int>(i) == default_id)
        gtk_widget_grab_focus(button);
    }