Add an abstract version of Drupal\page_manager\Plugin\DisplayVariant\BlockDisplayVariant from Page Manager

This is the next step.

Gonna give this a go either later tonight or tomorrow morning, had a quick talk with Tim & Kris regarding the associated traits, it got decided to also move these to ctools.

Here is the initial go at the move, fairly certain additional work is needed (like tests)

Here is a re-write of them

Heya, so unfortunately I think we're going to do this first because its blocking a whole bunch of issues.

Here is some re-writing with tests that need to be redone by Tim.

This is a review of 8, should basically apply to 10.

1. +++ b/src/Form/AjaxFormTrait.php
   @@ -0,0 +1,48 @@
   +  protected function getAjaxAttributes() {
   +    return [
   +      'class' => ['use-ajax'],
   +      'data-dialog-type' => 'modal',
   +      'data-dialog-options' => Json::encode([
   +        'width' => 'auto',
   +      ]),
   +    ];
   +  }
   +
   +  /**
   +   * Gets attributes for use with an add button AJAX modal.
   +   *
   +   * @return array
   +   */
   +  protected function getAjaxButtonAttributes() {
   +    return NestedArray::mergeDeep($this->getAjaxAttributes(), [
   +      'class' => [
   +        'button',
   +        'button--small',
   +        'button-action',
   +      ],
   +    ]);
   

   Not a problem for this code move, but I think we should consider making these static methods.

2. +++ b/src/Plugin/BlockVariantTrait.php
   @@ -0,0 +1,120 @@
   +  public function getRegionNames() {
   +    return [
   +      'top' => 'Top',
   +      'bottom' => 'Bottom',
   +    ];
   +  }
   

   Don't implement this. The user of the trait will need to manually implement this method.

3. +++ b/src/Plugin/ConditionVariantInterface.php
   @@ -0,0 +1,92 @@
   +<?php
   +
   +/**
   + * @file
   + * Contains \Drupal\ctools\Plugin\ConditionVariantInterface.
   + */
   +
   +namespace Drupal\ctools\Plugin;
   +
   +use Drupal\Core\Display\VariantInterface;
   +
   +/**
   + * Provides an interface for variant plugins that use condition plugins.
   + */
   +interface ConditionVariantInterface extends VariantInterface {
   

   Ok... so I'll move this to ctools, but no one can ever ever use this beyond the scope of this patch because we need to move this back out ultimately and apply these methods to the PageVariant entity we have pending.

4. +++ b/src/Plugin/ContextAwareVariantInterface.php
   @@ -0,0 +1,33 @@
   +<?php
   +
   +/**
   + * @file
   + * Contains \Drupal\ctools\Plugin\ContextAwareVariantInterface.
   + */
   +
   +namespace Drupal\ctools\Plugin;
   +
   +/**
   + * Provides an interface for variant plugins that are context-aware.
   + */
   +interface ContextAwareVariantInterface {
   

   We're trying to get this into core right now, so we're likely to remove this shortly, but ok.

Also there are 21 use statements on our BlockDisplayVariant... I didn't apply this code yet, are they all used? Please delete those which aren't if any.

Eclipse

Here are some other changes based on EclipseGC's review. Still need one test done but lets see if this passes the others.

Try it again.

A couple bugs still. Since VariantBase now uses RefinableCacheableDependencyTrait, we cannot use it while extending.

More fixes.

Committed!