WebAudio: Add IDL interface for AudioDestinationNode

This is an AudioNode representing the final audio destination and is
what the user will ultimately hear.

This node is used as one of the connecting nodes in athenacrisis.com

Add a placeholder for the interface without anything backing it for now.

Tests/LibWeb/Text/expected/all-window-properties.txt

@@ -14,6 +14,7 @@ Audio
 AudioBuffer
 AudioBufferSourceNode
 AudioContext
+AudioDestinationNode
 AudioNode
 AudioParam
 AudioScheduledSourceNode

Userland/Libraries/LibWeb/CMakeLists.txt

@@ -684,6 +684,7 @@ set(SOURCES
     WebAudio/AudioBuffer.cpp
     WebAudio/AudioBufferSourceNode.cpp
     WebAudio/AudioContext.cpp
+    WebAudio/AudioDestinationNode.cpp
     WebAudio/AudioNode.cpp
     WebAudio/AudioParam.cpp
     WebAudio/AudioScheduledSourceNode.cpp

Userland/Libraries/LibWeb/Forward.h

@@ -712,6 +712,7 @@ class Table;
 namespace Web::WebAudio {
 class AudioBuffer;
 class AudioBufferSourceNode;
+class AudioDestinationNode;
 class AudioContext;
 class AudioNode;
 class AudioParam;

Userland/Libraries/LibWeb/WebAudio/AudioDestinationNode.cpp

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Bindings/AudioDestinationNodePrototype.h>
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/HTML/EventNames.h>
+#include <LibWeb/WebAudio/AudioDestinationNode.h>
+
+namespace Web::WebAudio {
+
+JS_DEFINE_ALLOCATOR(AudioDestinationNode);
+
+AudioDestinationNode::AudioDestinationNode(JS::Realm& realm, JS::NonnullGCPtr<BaseAudioContext> context)
+    : AudioNode(realm, context)
+{
+}
+
+AudioDestinationNode::~AudioDestinationNode() = default;
+
+void AudioDestinationNode::initialize(JS::Realm& realm)
+{
+    Base::initialize(realm);
+    WEB_SET_PROTOTYPE_FOR_INTERFACE(AudioDestinationNode);
+}
+
+void AudioDestinationNode::visit_edges(Cell::Visitor& visitor)
+{
+    Base::visit_edges(visitor);
+}
+
+}

Userland/Libraries/LibWeb/WebAudio/AudioDestinationNode.h

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2024, Shannon Booth <shannon@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <LibWeb/WebAudio/AudioNode.h>
+
+namespace Web::WebAudio {
+
+// https://webaudio.github.io/web-audio-api/#AudioDestinationNode
+class AudioDestinationNode : public AudioNode {
+    WEB_PLATFORM_OBJECT(AudioDestinationNode, AudioNode);
+    JS_DECLARE_ALLOCATOR(AudioDestinationNode);
+
+public:
+    virtual ~AudioDestinationNode() override;
+
+protected:
+    AudioDestinationNode(JS::Realm&, JS::NonnullGCPtr<BaseAudioContext>);
+
+    virtual void initialize(JS::Realm&) override;
+    virtual void visit_edges(Cell::Visitor&) override;
+};
+
+}

Userland/Libraries/LibWeb/WebAudio/AudioDestinationNode.idl

@@ -0,0 +1,7 @@
+#import <WebAudio/AudioNode.idl>
+
+// https://webaudio.github.io/web-audio-api/#AudioDestinationNode
+[Exposed=Window]
+interface AudioDestinationNode : AudioNode {
+    [FIXME] readonly attribute unsigned long maxChannelCount;
+};

Userland/Libraries/LibWeb/idl_files.cmake

@@ -312,6 +312,7 @@ libweb_js_bindings(WebAssembly/WebAssembly NAMESPACE)
 libweb_js_bindings(WebAudio/AudioBuffer)
 libweb_js_bindings(WebAudio/AudioBufferSourceNode)
 libweb_js_bindings(WebAudio/AudioContext)
+libweb_js_bindings(WebAudio/AudioDestinationNode)
 libweb_js_bindings(WebAudio/AudioNode)
 libweb_js_bindings(WebAudio/AudioParam)
 libweb_js_bindings(WebAudio/AudioScheduledSourceNode)