LibWeb: Automatically disconnect all testing gamepads on test completion

Connected gamepads are stored on the Navigator, which means that when we
navigate to a new test, they stick around, including the virtual ones
we create for testing purposes. This caused issues such as the one
fixed in #7329 where failing to manually disconnect a virtual gamepad
meant that it would interfere with subsequent tests.

We don't want to rely on tests cleaning things up correctly, so this
commit introduces an automatic clean-up of these virtual gamepads.
InternalGamepad objects are now tracked in Internals, and all
disconnected in `Internals::perform_per_test_cleanup()`. It's named
generically as I'm expecting other systems (eg, localStorage or
cookies) to want similar cleanup between tests, but implementing those
is left as an exercise for a future person.

This method is called from signal_test_is_done(). This method is always
called in the case where the test completes. A test that crashes means
the WebContent isn't reused. A test that times out should also not have
its WebContent process reused, though it's not clear to me what we
currently do there.

Verified by commenting-out the `gamepad.disconnect()` line from the
Text/input/GamepadAPI/gamepad-is-available-in-new-navigables.html test
and then running:

```bash
for run in {1..20}; do
  Meta/ladybird.py run test-web -s -j1 -f GamepadAPI;
done
```

Libraries/LibWeb/Internals/InternalGamepad.cpp

@@ -7,6 +7,7 @@
 #include <LibWeb/Bindings/InternalGamepadPrototype.h>
 #include <LibWeb/Bindings/Intrinsics.h>
 #include <LibWeb/Internals/InternalGamepad.h>
+#include <LibWeb/Internals/Internals.h>
 
 #include <SDL3/SDL_gamepad.h>
 #include <SDL3/SDL_joystick.h>
@@ -61,8 +62,9 @@ static SDLCALL bool rumble_triggers(void* user_data, u16 left_rumble, u16 right_
     return true;
 }
 
-InternalGamepad::InternalGamepad(JS::Realm& realm)
+InternalGamepad::InternalGamepad(JS::Realm& realm, GC::Ref<Internals> internals)
     : Bindings::PlatformObject(realm)
+    , m_internals(internals)
 {
     SDL_VirtualJoystickDesc virtual_joystick_desc {};
     SDL_INIT_INTERFACE(&virtual_joystick_desc);
@@ -108,6 +110,7 @@ void InternalGamepad::visit_edges(Cell::Visitor& visitor)
     Base::visit_edges(visitor);
     visitor.visit(m_received_rumble_effects);
     visitor.visit(m_received_rumble_trigger_effects);
+    visitor.visit(m_internals);
 }
 
 void InternalGamepad::finalize()
@@ -174,6 +177,7 @@ void InternalGamepad::received_rumble_triggers(u16 left_rumble, u16 right_rumble
 
 void InternalGamepad::disconnect()
 {
+    m_internals->disconnect_virtual_gamepad(*this);
     SDL_CloseJoystick(m_sdl_joystick);
     SDL_DetachVirtualJoystick(m_sdl_joystick_id);
 }

Libraries/LibWeb/Internals/InternalGamepad.h

@@ -38,7 +38,7 @@ public:
     void disconnect();
 
 private:
-    InternalGamepad(JS::Realm&);
+    InternalGamepad(JS::Realm&, GC::Ref<Internals>);
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
     virtual void finalize() override;
@@ -47,6 +47,7 @@ private:
     SDL_Joystick* m_sdl_joystick;
     Vector<GC::Ref<JS::Object>> m_received_rumble_effects;
     Vector<GC::Ref<JS::Object>> m_received_rumble_trigger_effects;
+    GC::Ref<Internals> m_internals;
 };
 
 }

Libraries/LibWeb/Internals/Internals.cpp

@@ -49,8 +49,15 @@ void Internals::initialize(JS::Realm& realm)
     Base::initialize(realm);
 }
 
+void Internals::visit_edges(Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_gamepads);
+}
+
 void Internals::signal_test_is_done(String const& text)
 {
+    perform_per_test_cleanup();
     page().client().page_did_finish_test(text);
 }
 
@@ -407,7 +414,23 @@ void Internals::handle_sdl_input_events()
 GC::Ref<InternalGamepad> Internals::connect_virtual_gamepad()
 {
     auto& realm = this->realm();
-    return realm.create<InternalGamepad>(realm);
+    auto gamepad = realm.create<InternalGamepad>(realm, *this);
+    m_gamepads.append(gamepad);
+    return gamepad;
+}
+
+void Internals::disconnect_virtual_gamepad(GC::Ref<InternalGamepad> gamepad)
+{
+    if (auto index = m_gamepads.find_first_index(gamepad); index.has_value())
+        m_gamepads.remove(index.value());
+}
+
+void Internals::perform_per_test_cleanup()
+{
+    // Detach any virtual gamepads
+    for (auto gamepad : m_gamepads)
+        gamepad->disconnect();
+    m_gamepads.clear();
 }
 
 }

Libraries/LibWeb/Internals/Internals.h

@@ -80,14 +80,20 @@ public:
     void handle_sdl_input_events();
 
     GC::Ref<InternalGamepad> connect_virtual_gamepad();
+    void disconnect_virtual_gamepad(GC::Ref<InternalGamepad>);
+
+    void perform_per_test_cleanup();
 
 private:
     explicit Internals(JS::Realm&);
 
     virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(Visitor&) override;
 
     void click(double x, double y, UIEvents::MouseButton);
     void mouse_down(double x, double y, UIEvents::MouseButton);
+
+    Vector<GC::Ref<InternalGamepad>> m_gamepads;
 };
 
 }