Move block code from menu_ui_menu_delete() into block_menu_delete()

Not sure if this should be in menu_delete() but for some reason I feel like having an implementation of hook_menu_delete seems more correct. Seems to separate the code better.

This no longer applies.

It also needs changing as I don't think we use "delta" anymore. See the new implementation in the block.module

I've re-done this patch to work with the most recent changes in Drupal 8 core.

Please have a look and review when you can.

Great, thanks.

+++ b/core/modules/menu/menu.module
@@ -226,6 +226,11 @@ function menu_menu_delete(Menu $menu) {
+    foreach (entity_load_multiple('block') as $block) {
+      if ($block->get('plugin') == 'system_menu_block:' . $menu->id()) {

This could actually be foreach (entity_load_multiple_by_properties('block', array('plugin' => 'system_menu_block:' . $menu->id())) as $block) {

Good call. New patch attached.

Hm. the menu blocks are provided by system.module, so it's not really clear to me what belongs in which module.

Ugh, yes, I always forget this. Which is part of why #2085243: Rename Menu module into Menu UI module needs to happen.

Added Tim's feedback from #5

Thanks!

Reroll

Sounds like a duplicate of #2031859: Invoke an event[s] when a plugin ID disappears tbh.

.