LibWeb: Refactor all LabelableNode subclasses + input event handling :^)

This commit is messy due to the Paintable and Layout classes being
tangled together.

The RadioButton, CheckBox and ButtonBox classes are now subclasses of
FormAssociatedLabelableNode. This subclass separates these layout nodes
from LabelableNode, which is also the superclass of non-form associated
labelable nodes (Progress).

ButtonPaintable, CheckBoxPaintable and RadioButtonPaintable no longer
call events on DOM nodes directly from their mouse event handlers;
instead, all the functionality is now directly in EventHandler, which
dispatches the related events. handle_mousedown and related methods
return a bool indicating whether the event handling should proceed.

Paintable classes can now return an alternative DOM::Node which should
be the target of the mouse event. Labels use this to indicate that the
labeled control should be the target of the mouse events.

HTMLInputElement put its activation behavior on run_activation_behavior,
which wasn't actually called anywhere and had to be manually called by
other places. We now use activation_behavior which is used by
EventDispatcher.

This commit also brings HTMLInputElement closer to spec by removing the
did_foo functions that did ad-hoc event dispatching and unifies the
behavior under run_input_activation_behavior.

2 files changed, 2 insertions, 3 deletions

diff --git a/Userland/Libraries/LibWeb/DOM/EventDispatcher.cpp b/Userland/Libraries/LibWeb/DOM/EventDispatcher.cpp
index 208920cdee..9584813bed 100644
--- a/Userland/Libraries/LibWeb/DOM/EventDispatcher.cpp
+++ b/Userland/Libraries/LibWeb/DOM/EventDispatcher.cpp
@@ -328,6 +328,7 @@ bool EventDispatcher::dispatch(NonnullRefPtr<EventTarget> target, NonnullRefPtr<
         if (!event->cancelled()) {
             // NOTE: Since activation_target is set, it will have activation behavior.
             activation_target->activation_behavior(event);
+            activation_target->legacy_cancelled_activation_behavior_was_not_called();
         } else {
             activation_target->legacy_cancelled_activation_behavior();
         }
diff --git a/Userland/Libraries/LibWeb/DOM/EventTarget.h b/Userland/Libraries/LibWeb/DOM/EventTarget.h
index 8d5fb9b47c..75586c3d36 100644
--- a/Userland/Libraries/LibWeb/DOM/EventTarget.h
+++ b/Userland/Libraries/LibWeb/DOM/EventTarget.h
@@ -55,13 +55,11 @@ public:
     // NOTE: These only exist for checkbox and radio input elements.
     virtual void legacy_pre_activation_behavior() { }
     virtual void legacy_cancelled_activation_behavior() { }
+    virtual void legacy_cancelled_activation_behavior_was_not_called() { }
 
     Bindings::CallbackType* event_handler_attribute(FlyString const& name);
     void set_event_handler_attribute(FlyString const& name, Optional<Bindings::CallbackType>);
 
-    // https://dom.spec.whatwg.org/#eventtarget-activation-behavior
-    virtual void run_activation_behavior() { }
-
 protected:
     EventTarget();