Rework public API based on events

src/Events/BuildClientView.php

@@ -0,0 +1,34 @@
+<?php namespace Flarum\Events;
+
+use Flarum\Support\ClientAction;
+use Flarum\Support\ClientView;
+
+class BuildClientView
+{
+    /**
+     * @var ClientAction
+     */
+    protected $action;
+
+    /**
+     * @var ClientView
+     */
+    protected $view;
+
+    /**
+     * @var array
+     */
+    protected $keys;
+
+    /**
+     * @param ClientAction $action
+     * @param ClientView $view
+     * @param array $keys
+     */
+    public function __construct($action, $view, &$keys)
+    {
+        $this->action = $action;
+        $this->view = $view;
+        $this->keys = &$keys;
+    }
+}