LibMedia: Remove WrapperTimeProvider in favor of diamond inheritance

Libraries/LibMedia/MediaPipelineNode.h

@@ -0,0 +1,18 @@
+/*
+ * Copyright (c) 2026-present, the Ladybird developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/AtomicRefCounted.h>
+
+namespace Media {
+
+class MediaPipelineNode : public AtomicRefCounted<MediaPipelineNode> {
+public:
+    virtual ~MediaPipelineNode() = default;
+};
+
+}

Libraries/LibMedia/PlaybackManager.cpp

@@ -11,7 +11,6 @@
 #include <LibMedia/Providers/AudioDataProvider.h>
 #include <LibMedia/Providers/GenericTimeProvider.h>
 #include <LibMedia/Providers/VideoDataProvider.h>
-#include <LibMedia/Providers/WrapperTimeProvider.h>
 #include <LibMedia/Sinks/AudioMixingSink.h>
 #include <LibMedia/Sinks/DisplayingVideoSink.h>
 #include <LibMedia/Track.h>
@@ -117,7 +116,7 @@ DecoderErrorOr<void> PlaybackManager::prepare_playback_from_demuxer(WeakPlayback
 
         if (!self->m_audio_output_disabled && !self->m_audio_sink && !self->m_audio_tracks.is_empty()) {
             self->m_audio_sink = MUST(AudioMixingSink::try_create());
-            self->set_time_provider(make_ref_counted<WrapperTimeProvider<AudioMixingSink>>(*self->m_audio_sink));
+            self->set_time_provider(*self->m_audio_sink);
             self->m_audio_sink->on_audio_output_error = [self](Error&& error) {
                 if (!self)
                     return;

Libraries/LibMedia/Providers/MediaTimeProvider.h

@@ -6,12 +6,12 @@
 
 #pragma once
 
-#include <AK/AtomicRefCounted.h>
 #include <AK/Time.h>
+#include <LibMedia/MediaPipelineNode.h>
 
 namespace Media {
 
-class MediaTimeProvider : public AtomicRefCounted<MediaTimeProvider> {
+class MediaTimeProvider : public virtual MediaPipelineNode {
 public:
     virtual ~MediaTimeProvider() = default;
 

Libraries/LibMedia/Providers/WrapperTimeProvider.h

@@ -1,31 +0,0 @@
-/*
- * Copyright (c) 2025, Gregory Bertilson <gregory@ladybird.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <LibMedia/Providers/MediaTimeProvider.h>
-
-namespace Media {
-
-template<typename T>
-class WrapperTimeProvider final : public MediaTimeProvider {
-public:
-    WrapperTimeProvider(T& inner)
-        : m_inner(inner)
-    {
-    }
-    virtual ~WrapperTimeProvider() override = default;
-
-    virtual AK::Duration current_time() const override { return m_inner->current_time(); }
-    virtual void resume() override { m_inner->resume(); }
-    virtual void pause() override { m_inner->pause(); }
-    virtual void set_time(AK::Duration time) override { m_inner->set_time(time); }
-
-private:
-    NonnullRefPtr<T> m_inner;
-};
-
-}

Libraries/LibMedia/Sinks/AudioMixingSink.h

@@ -18,7 +18,8 @@
 
 namespace Media {
 
-class MEDIA_API AudioMixingSink final : public AudioSink {
+class MEDIA_API AudioMixingSink final : public AudioSink
+    , public MediaTimeProvider {
     class AudioMixingSinkWeakReference;
 
 private:
@@ -32,13 +33,10 @@ public:
     virtual void set_provider(Track const&, RefPtr<AudioDataProvider> const&) override;
     virtual RefPtr<AudioDataProvider> provider(Track const&) const override;
 
-    // This section implements the pure virtuals in MediaTimeProvider.
-    // AudioMixingSink cannot inherit from MediaTimeProvider, as AudioSink and MediaTimeProvider both inherit from
-    // AtomicRefCounted. In order to use AudioMixingSink as a MediaTimeProvider, wrap it with WrapperTimeProvider.
-    AK::Duration current_time() const;
-    void resume();
-    void pause();
-    void set_time(AK::Duration);
+    virtual AK::Duration current_time() const override;
+    virtual void resume() override;
+    virtual void pause() override;
+    virtual void set_time(AK::Duration) override;
 
     void set_volume(double);
 

Libraries/LibMedia/Sinks/AudioSink.h

@@ -6,15 +6,15 @@
 
 #pragma once
 
-#include <AK/AtomicRefCounted.h>
 #include <LibMedia/AudioBlock.h>
 #include <LibMedia/Export.h>
 #include <LibMedia/Forward.h>
+#include <LibMedia/MediaPipelineNode.h>
 #include <LibMedia/Track.h>
 
 namespace Media {
 
-class MEDIA_API AudioSink : public AtomicRefCounted<AudioSink> {
+class MEDIA_API AudioSink : public virtual MediaPipelineNode {
 public:
     virtual ~AudioSink() = default;