Begin scaffolding keyboard nav

src/dusk/ui/component.cpp

@@ -15,6 +15,20 @@ void Component::update() {
     }
 }
 
+bool Component::focus() {
+    // Can we focus self?
+    if (mRoot->Focus(true)) {
+        return true;
+    }
+    // Otherwise, try to focus a child
+    for (const auto& child : mChildren) {
+        if (child->focus()) {
+            return true;
+        }
+    }
+    return false;
+}
+
 Rml::Element* Component::append(Rml::Element* parent, const Rml::String& tag) {
     if (parent == nullptr) {
         return nullptr;
@@ -35,6 +49,15 @@ void Component::listen(Rml::Element* element, Rml::EventId event,
         std::make_unique<ScopedEventListener>(element, event, std::move(callback), capture));
 }
 
+bool Component::contains(Rml::Element* element) const {
+    for (const auto* node = element; node != nullptr; node = node->GetParentNode()) {
+        if (node == mRoot) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void Component::clear_children() {
     mChildren.clear();
     while (mRoot->GetNumChildren() > 0) {