LibWeb: Add AnimationTimeline IDL object

Userland/Libraries/LibWeb/Animations/AnimationTimeline.cpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2023, Matthew Olsson <mattco@serenityos.org>.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Animations/AnimationTimeline.h>
+#include <LibWeb/DOM/Document.h>
+
+namespace Web::Animations {
+
+WebIDL::ExceptionOr<void> AnimationTimeline::set_current_time(Optional<double> value)
+{
+    if (value == m_current_time)
+        return {};
+
+    if (m_is_monotonically_increasing && m_current_time.has_value()) {
+        if (!value.has_value() || value.value() < m_current_time.value())
+            m_is_monotonically_increasing = false;
+    }
+
+    m_current_time = value;
+
+    return {};
+}
+
+void AnimationTimeline::set_associated_document(JS::GCPtr<DOM::Document> document)
+{
+    m_associated_document = document;
+}
+
+// https://www.w3.org/TR/web-animations-1/#inactive-timeline
+bool AnimationTimeline::is_inactive() const
+{
+    // A timeline is considered to be inactive when its time value is unresolved.
+    return !m_current_time.has_value();
+}
+
+AnimationTimeline::AnimationTimeline(JS::Realm& realm)
+    : Bindings::PlatformObject(realm)
+{
+}
+
+void AnimationTimeline::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    set_prototype(&Bindings::ensure_web_prototype<Bindings::AnimationTimelinePrototype>(realm, "AnimationTimeline"));
+}
+
+void AnimationTimeline::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+    visitor.visit(m_associated_document);
+}
+
+}