Add a base class for partial matchers.

core/lib/Drupal/Core/Routing/HttpMethodMatcher.php

@@ -4,19 +4,12 @@ namespace Drupal\Core\Routing;
 
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\Routing\RouteCollection;
+use Symfony\Component\Routing\Exception\MethodNotAllowedException;
 
 /**
  * This class filters routes based on their HTTP Method.
  */
-class HttpMethodMatcher implements PartialMatcherInterface {
-
-  protected $routes;
-
-  public function setCollection(RouteCollection $routes) {
-    $this->routes = $routes;
-
-    return $this;
-  }
+class HttpMethodMatcher extends PartialMatcher {
 
   /**
    * Matches a request against multiple routes.

core/lib/Drupal/Core/Routing/PartialMatcher.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Drupal\Core\Routing;
+
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\Routing\RouteCollection;
+
+/**
+ * Utility base class for partial matchers.
+ */
+abstract class PartialMatcher implements PartialMatcherInterface {
+
+  /**
+   * The RouteCollection this matcher should match against.
+   *
+   * @var RouteCollection
+   */
+  protected $routes;
+
+  /**
+   * Sets the route collection this matcher should use.
+   *
+   * @param RouteCollection $collection
+   *   The collection against which to match.
+   *
+   * @return PartialMatcherInterface
+   *   The current matcher.
+   */
+  public function setCollection(RouteCollection $collection) {
+    $this->routes = $collection;
+
+    return $this;
+  }
+
+}