Move baseFieldDefinitions from storage to entity classes

The attached patch basically does that except that I haven't moved the implementations yet, I'm forwarding the call to the storage controller.

#1: move-basefielddefinitions-2024963-1.patch queued for re-testing.

Re-roll and moved definitions around. Allows us to get rid of a storage controller or two, but most still have some methods in there. Noticed a problem in EntityTestStorageController, we can't remove that one because it needs access to the entity type in create(). We should pass that through to the static functions...

An unrelated change ended up being in the patch.

Removed the call to the new removed method on the storage controller.

This should be green.

This is a not yet approved API change.

This only impacts entities that already switched to EntityNG, of which I doubt there are many. Fetching the field definitions works just as it did before. Updating for this is easy, just move the method from the storage controller to the entity class and make it static.

This change makes total sense - approving.

+++ b/core/modules/views_ui/lib/Drupal/views_ui/ViewUI.phpundefined
@@ -1236,4 +1236,11 @@ public function mergeDefaultDisplaysOptions() {
+  public static function baseFieldDefinitions($entity_type) {
+    return array();

Let's delegate this to the real View entity as ViewUI is a decorator used to add functionality when editing a View in the UI. Just in case config entities start to use this. How about something like return View::baseFieldDefinitions($entity_type);?

+++ b/core/lib/Drupal/Core/Entity/EntityInterface.phpundefined
@@ -326,4 +326,19 @@ public function isTranslatable();
+   *
+   * @param string $entity_type
+   *   The name of the entity type to return properties from.

I think this should just be The entity type to return properties for. as this is consistent with other similar function params. I also think it might worth documenting the use case as it is never used in core AFAICS.

Berdir mentioned on IRC that once #2004244: Move entity revision, content translation, validation and field methods to ContentEntityInterface lands we will be able to remove the ViewUI code.

In that case I think we should only fix up the comment and outline the use-case for passing in $entity_type.

Something like this?

#15: move-basefielddefinitions-2024963-15.patch queued for re-testing.

Committed 48ddeb4 and pushed to 8.x. Thanks!

Will provide a change notice around the whole field definition/base field definition stuff asap.

Quick follow-up: #2075503: Wrong issue linked in @todo in ViewUI::baseFieldDefinitions()

Added this to https://drupal.org/node/1806650, and more importantly, wrote a documentation page about all this at https://drupal.org/node/2078241. Reviews and improvements welcome!