[TwigBundle] removed Stopwatch Twig extension when the Stopwatch component is not available

src/Symfony/Bundle/TwigBundle/DependencyInjection/Compiler/ExtensionPass.php

@@ -75,5 +75,9 @@ class ExtensionPass implements CompilerPassInterface
         if (class_exists('Symfony\Component\Yaml\Parser')) {
             $container->getDefinition('twig.extension.yaml')->addTag('twig.extension');
         }
+
+        if (class_exists('Symfony\Component\Stopwatch\Stopwatch')) {
+            $container->getDefinition('twig.extension.debug.stopwatch')->addTag('twig.extension');
+        }
     }
 }

src/Symfony/Bundle/TwigBundle/Resources/config/twig.xml

@@ -98,7 +98,6 @@
         <service id="twig.extension.yaml" class="Symfony\Bridge\Twig\Extension\YamlExtension" public="false" />
 
         <service id="twig.extension.debug.stopwatch" class="Symfony\Bridge\Twig\Extension\StopwatchExtension" public="false">
-            <tag name="twig.extension" />
             <argument type="service" id="debug.stopwatch" on-invalid="ignore" />
             <argument>%kernel.debug%</argument>
         </service>