Issue #2266377 by dawehner, bkosborne, pwolanin: Speed up UrlGenerator a little by setting the 'external' option in the Url object .

core/lib/Drupal/Core/Url.php

@@ -171,6 +171,8 @@ class Url extends DependencySerialization {
     // Set empty route name and parameters.
     $this->routeName = NULL;
     $this->routeParameters = array();
+    // Flag the path as external so the UrlGenerator does not need to check.
+    $this->options['external'] = TRUE;
 
     return $this;
   }

core/tests/Drupal/Tests/Core/ExternalUrlTest.php

@@ -64,9 +64,7 @@ class ExternalUrlTest extends UnitTestCase {
     $this->urlGenerator = $this->getMock('Drupal\Core\Routing\UrlGeneratorInterface');
     $this->urlGenerator->expects($this->any())
       ->method('generateFromPath')
-      ->will($this->returnCallback(function ($path) {
+      ->will($this->returnArgument(0));
-        return $path;
-      }));
 
     $this->router = $this->getMock('Drupal\Tests\Core\Routing\TestRouterInterface');
     $container = new ContainerBuilder();
@@ -143,7 +141,7 @@ class ExternalUrlTest extends UnitTestCase {
   public function testToArray(Url $url) {
     $expected = array(
       'path' => $this->path,
-      'options' => array(),
+      'options' => array('external' => TRUE),
     );
     $this->assertSame($expected, $url->toArray());
   }

core/tests/Drupal/Tests/Core/Utility/LinkGeneratorTest.php

@@ -17,6 +17,9 @@ use Drupal\Tests\UnitTestCase;
  *
  * @see \Drupal\Core\Utility\LinkGenerator
  *
+ * @group Drupal
+ * @group Utility
+ *
  * @coversDefaultClass \Drupal\Core\Utility\LinkGenerator
  */
 class LinkGeneratorTest extends UnitTestCase {
@@ -159,8 +162,8 @@ class LinkGeneratorTest extends UnitTestCase {
   public function testGenerateFromUrlExternal() {
     $this->urlGenerator->expects($this->once())
       ->method('generateFromPath')
-      ->with('http://drupal.org', array('set_active_class' => TRUE) + $this->defaultOptions)
+      ->with('http://drupal.org', array('set_active_class' => TRUE, 'external' => TRUE) + $this->defaultOptions)
-      ->will($this->returnValue('http://drupal.org'));
+      ->will($this->returnArgument(0));
 
     $this->moduleHandler->expects($this->once())
       ->method('alter')