LibGUI: Scroll selection into view when the IconView is first laid out

If we set selection before the IconView is laid out, it has no size.
So it can't correctly calculate where to scroll. Forcing scroll after
the first resize fixes that.

Userland/Libraries/LibGUI/IconView.cpp

@@ -72,6 +72,12 @@ void IconView::resize_event(ResizeEvent& event)
 {
     AbstractView::resize_event(event);
     update_content_size();
+
+    if (!m_had_valid_size) {
+        m_had_valid_size = true;
+        if (!selection().is_empty())
+            scroll_into_view(selection().first());
+    }
 }
 
 void IconView::reinit_item_cache() const

Userland/Libraries/LibGUI/IconView.h

@@ -182,6 +182,8 @@ private:
     mutable bool m_item_data_cache_valid { false };
 
     bool m_changing_selection { false };
+
+    bool m_had_valid_size { false };
 };
 
 }