LibWeb: Use paintable to represent event tracking node

The use of layout nodes likely predated the paintable tree, but now
there is no point in introducing another level of indirection.

Userland/Libraries/LibWeb/HTML/BrowsingContext.cpp

@@ -297,6 +297,8 @@ void BrowsingContext::visit_edges(Cell::Visitor& visitor)
     visitor.visit(m_last_child);
     visitor.visit(m_next_sibling);
     visitor.visit(m_previous_sibling);
+
+    m_event_handler.visit_edges(visitor);
 }
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#bc-traversable

Userland/Libraries/LibWeb/Page/EventHandler.cpp

@@ -836,9 +836,9 @@ bool EventHandler::handle_keyup(KeyCode key, u32 modifiers, u32 code_point)
     return fire_keyboard_event(UIEvents::EventNames::keyup, m_browsing_context, key, modifiers, code_point);
 }
 
-void EventHandler::set_mouse_event_tracking_layout_node(Layout::Node* layout_node)
+void EventHandler::set_mouse_event_tracking_paintable(Painting::Paintable* paintable)
 {
-    m_mouse_event_tracking_layout_node = layout_node;
+    m_mouse_event_tracking_paintable = paintable;
 }
 
 CSSPixelPoint EventHandler::compute_mouse_event_client_offset(CSSPixelPoint event_page_position) const
@@ -880,11 +880,11 @@ CSSPixelPoint EventHandler::compute_mouse_event_movement(CSSPixelPoint screen_po
 
 Optional<EventHandler::Target> EventHandler::target_for_mouse_position(CSSPixelPoint position)
 {
-    if (m_mouse_event_tracking_layout_node) {
-        if (m_mouse_event_tracking_layout_node->paintable()->wants_mouse_events())
-            return Target { m_mouse_event_tracking_layout_node->paintable(), {} };
+    if (m_mouse_event_tracking_paintable) {
+        if (m_mouse_event_tracking_paintable->wants_mouse_events())
+            return Target { m_mouse_event_tracking_paintable, {} };
 
-        m_mouse_event_tracking_layout_node = nullptr;
+        m_mouse_event_tracking_paintable = nullptr;
     }
 
     if (auto result = paint_root()->hit_test(position, Painting::HitTestType::Exact); result.has_value())
@@ -893,4 +893,9 @@ Optional<EventHandler::Target> EventHandler::target_for_mouse_position(CSSPixelP
     return {};
 }
 
+void EventHandler::visit_edges(JS::Cell::Visitor& visitor) const
+{
+    visitor.visit(m_mouse_event_tracking_paintable);
+}
+
 }

Userland/Libraries/LibWeb/Page/EventHandler.h

@@ -12,6 +12,7 @@
 #include <Kernel/API/KeyCode.h>
 #include <LibGUI/Forward.h>
 #include <LibGfx/Forward.h>
+#include <LibJS/Heap/Cell.h>
 #include <LibJS/Heap/GCPtr.h>
 #include <LibWeb/Forward.h>
 #include <LibWeb/Page/EditEventHandler.h>
@@ -33,10 +34,12 @@ public:
     bool handle_keydown(KeyCode, unsigned modifiers, u32 code_point);
     bool handle_keyup(KeyCode, unsigned modifiers, u32 code_point);
 
-    void set_mouse_event_tracking_layout_node(Layout::Node*);
+    void set_mouse_event_tracking_paintable(Painting::Paintable*);
 
     void set_edit_event_handler(NonnullOwnPtr<EditEventHandler> value) { m_edit_event_handler = move(value); }
 
+    void visit_edges(JS::Cell::Visitor& visitor) const;
+
 private:
     bool focus_next_element();
     bool focus_previous_element();
@@ -59,7 +62,7 @@ private:
 
     bool m_in_mouse_selection { false };
 
-    WeakPtr<Layout::Node> m_mouse_event_tracking_layout_node;
+    JS::GCPtr<Painting::Paintable> m_mouse_event_tracking_paintable;
 
     NonnullOwnPtr<EditEventHandler> m_edit_event_handler;
 

Userland/Libraries/LibWeb/Painting/LabelablePaintable.cpp

@@ -42,7 +42,7 @@ LabelablePaintable::DispatchEventOfSameName LabelablePaintable::handle_mousedown
 
     set_being_pressed(true);
     m_tracking_mouse = true;
-    browsing_context().event_handler().set_mouse_event_tracking_layout_node(&layout_box());
+    browsing_context().event_handler().set_mouse_event_tracking_paintable(this);
     return DispatchEventOfSameName::Yes;
 }
 
@@ -57,7 +57,7 @@ LabelablePaintable::DispatchEventOfSameName LabelablePaintable::handle_mouseup(B
 
     set_being_pressed(false);
     m_tracking_mouse = false;
-    browsing_context().event_handler().set_mouse_event_tracking_layout_node(nullptr);
+    browsing_context().event_handler().set_mouse_event_tracking_paintable(nullptr);
     return DispatchEventOfSameName::Yes;
 }
 

Userland/Libraries/LibWeb/Painting/MediaPaintable.cpp

@@ -284,7 +284,7 @@ MediaPaintable::DispatchEventOfSameName MediaPaintable::handle_mousedown(Badge<E
     }
 
     if (media_element.layout_mouse_tracking_component({}).has_value())
-        const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_layout_node(&layout_node());
+        const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_paintable(this);
 
     return DispatchEventOfSameName::Yes;
 }
@@ -306,7 +306,7 @@ MediaPaintable::DispatchEventOfSameName MediaPaintable::handle_mouseup(Badge<Eve
             break;
         }
 
-        const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_layout_node(nullptr);
+        const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_paintable(nullptr);
         media_element.set_layout_mouse_tracking_component({}, {});
 
         return DispatchEventOfSameName::Yes;

Userland/Libraries/LibWeb/Painting/TextPaintable.cpp

@@ -42,7 +42,7 @@ TextPaintable::DispatchEventOfSameName TextPaintable::handle_mousedown(Badge<Eve
     if (!label)
         return DispatchEventOfSameName::No;
     const_cast<Layout::Label*>(label)->handle_mousedown_on_label({}, position, button);
-    const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_layout_node(&const_cast<Layout::TextNode&>(layout_node()));
+    const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_paintable(this);
     return DispatchEventOfSameName::Yes;
 }
 
@@ -53,7 +53,7 @@ TextPaintable::DispatchEventOfSameName TextPaintable::handle_mouseup(Badge<Event
         return DispatchEventOfSameName::No;
 
     const_cast<Layout::Label*>(label)->handle_mouseup_on_label({}, position, button);
-    const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_layout_node(nullptr);
+    const_cast<HTML::BrowsingContext&>(browsing_context()).event_handler().set_mouse_event_tracking_paintable(nullptr);
     return DispatchEventOfSameName::Yes;
 }