WV-4745: Add mudule_hander service trait.

src/Core/Extension/ModuleHandlerTrait.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace drunomics\ServiceUtils\Core\Extension;
+
+use Drupal\Core\Extension\ModuleHandlerInterface;
+
+/**
+ * Allows setter injection and simple usage of the service.
+ */
+trait ModuleHandlerTrait {
+
+  /**
+   * The module handler.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
+  /**
+   * Sets the module handler.
+   *
+   * @param \Drupal\Core\Extension\ModuleHandlerInterface $moduleHandler
+   *   The module handler.
+   *
+   * @return $this
+   */
+  public function setModuleHandler(ModuleHandlerInterface $moduleHandler) {
+    $this->moduleHandler = $moduleHandler;
+    return $this;
+  }
+
+  /**
+   * Gets the module handler.
+   *
+   * @return \Drupal\Core\Extension\ModuleHandlerInterface
+   *   The module handler.
+   */
+  public function getModuleHandler() {
+    if (empty($this->moduleHandler)) {
+      $this->moduleHandler = \Drupal::service('module_handler');
+    }
+    return $this->moduleHandler;
+  }
+
+}