Issue #3296952: Add an interface for addCacheableDependency()

core/lib/Drupal/Core/Cache/ObjectWithRefinableCacheabilityInterface.php

+<?php
+
+namespace Drupal\Core\Cache;
+
+/**
+ * Allows cacheability metadata to be added for the current runtime.
+ */
+interface ObjectWithRefinableCacheabilityInterface {
+
+  /**
+   * Adds a dependency on an object: merges its cacheability metadata.
+   *
+   * @param \Drupal\Core\Cache\CacheableDependencyInterface|object $other_object
+   *   The dependency. If the object implements CacheableDependencyInterface,
+   *   then its cacheability metadata will be used. Otherwise, the passed in
+   *   object must be assumed to be uncacheable, so max-age 0 is set.
+   *
+   * @return $this
+   *
+   * @see \Drupal\Core\Cache\CacheableMetadata::createFromObject()
+   */
+  public function addCacheableDependency($other_object);
+
+}