Tweak ContentInterface so that callables can be used as well

src/Admin/Content/AdminPayload.php

@@ -52,7 +52,7 @@ class AdminPayload implements ContentInterface
         $this->events = $events;
     }
 
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $settings = $this->settings->all();
 

src/Forum/Content/AssertRegistered.php

@@ -20,7 +20,7 @@ class AssertRegistered implements ContentInterface
 {
     use AssertPermissionTrait;
 
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $this->assertRegistered($request->getAttribute('actor'));
     }

src/Forum/Content/Discussion.php

@@ -49,7 +49,7 @@ class Discussion implements ContentInterface
         $this->view = $view;
     }
 
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $queryParams = $request->getQueryParams();
         $page = max(1, array_get($queryParams, 'page'));

src/Forum/Content/Index.php

@@ -44,7 +44,7 @@ class Index implements ContentInterface
     /**
      * {@inheritdoc}
      */
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $queryParams = $request->getQueryParams();
 

src/Frontend/Content/ContentInterface.php

@@ -20,5 +20,5 @@ interface ContentInterface
      * @param HtmlDocument $document
      * @param Request $request
      */
-    public function populate(HtmlDocument $document, Request $request);
+    public function __invoke(HtmlDocument $document, Request $request);
 }

src/Frontend/Content/CorePayload.php

@@ -41,7 +41,7 @@ class CorePayload implements ContentInterface
         $this->api = $api;
     }
 
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $document->payload = array_merge(
             $document->payload,

src/Frontend/Content/Layout.php

@@ -29,7 +29,7 @@ class Layout implements ContentInterface
         $this->layoutView = $layoutView;
     }
 
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $document->layoutView = $this->layoutView;
     }

src/Frontend/Content/Meta.php

@@ -16,7 +16,7 @@ use Psr\Http\Message\ServerRequestInterface as Request;
 
 class Meta implements ContentInterface
 {
-    public function populate(HtmlDocument $document, Request $request)
+    public function __invoke(HtmlDocument $document, Request $request)
     {
         $document->meta = array_merge($document->meta, $this->buildMeta($document));
         $document->head = array_merge($document->head, $this->buildHead($document));

src/Frontend/HtmlDocumentFactory.php

@@ -61,7 +61,7 @@ class HtmlDocumentFactory
     }
 
     /**
-     * @param ContentInterface $content
+     * @param ContentInterface|callable $content
      */
     public function add($content)
     {
@@ -116,7 +116,7 @@ class HtmlDocumentFactory
     protected function populate(HtmlDocument $view, Request $request)
     {
         foreach ($this->content as $content) {
-            $content->populate($view, $request);
+            $content($view, $request);
         }
     }