LibMedia: Replace FlyString with String for Matroska track attributes

The values stored by these are either going to be fairly unique or too
short to benefit from FlyString.

Author: Zaggy1024

Libraries/LibMedia/Containers/Matroska/Document.h

@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2021, Hunter Salyer <thefalsehonesty@gmail.com>
+ * Copyright (c) 2025, Gregory Bertilson <gregory@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -9,11 +10,10 @@
 #include <AK/ByteBuffer.h>
 #include <AK/ByteString.h>
 #include <AK/FixedArray.h>
-#include <AK/FlyString.h>
 #include <AK/HashMap.h>
 #include <AK/OwnPtr.h>
+#include <AK/String.h>
 #include <AK/Time.h>
-#include <AK/Utf8View.h>
 #include <LibMedia/Color/CodingIndependentCodePoints.h>
 
 namespace Media::Matroska {
@@ -116,10 +116,10 @@ class TrackEntry : public RefCounted<TrackEntry> {
     void set_track_uid(u64 track_uid) { m_track_uid = track_uid; }
     TrackType track_type() const { return m_track_type; }
     void set_track_type(TrackType track_type) { m_track_type = track_type; }
-    FlyString language() const { return m_language; }
-    void set_language(FlyString const& language) { m_language = language; }
-    FlyString codec_id() const { return m_codec_id; }
-    void set_codec_id(FlyString const& codec_id) { m_codec_id = codec_id; }
+    String language() const { return m_language; }
+    void set_language(String const& language) { m_language = language; }
+    String codec_id() const { return m_codec_id; }
+    void set_codec_id(String const& codec_id) { m_codec_id = codec_id; }
     ReadonlyBytes codec_private_data() const LIFETIME_BOUND { return m_codec_private_data.span(); }
     ErrorOr<void> set_codec_private_data(ReadonlyBytes codec_private_data)
     {
@@ -151,8 +151,8 @@ class TrackEntry : public RefCounted<TrackEntry> {
     u64 m_track_number { 0 };
     u64 m_track_uid { 0 };
     TrackType m_track_type { Invalid };
-    FlyString m_language = "eng"_fly_string;
-    FlyString m_codec_id;
+    String m_language = "eng"_string;
+    String m_codec_id;
     FixedArray<u8> m_codec_private_data;
     double m_timestamp_scale { 1 };
     u64 m_codec_delay { 0 };

Libraries/LibMedia/Containers/Matroska/MatroskaDemuxer.cpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
+ * Copyright (c) 2022-2025, Gregory Bertilson <gregory@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -115,7 +115,7 @@ DecoderErrorOr<MatroskaDemuxer::TrackStatus*> MatroskaDemuxer::get_track_status(
     return &m_track_statuses.get(track).release_value();
 }
 
-CodecID MatroskaDemuxer::get_codec_id_for_string(FlyString const& codec_id)
+static CodecID get_codec_id_for_string(String const& codec_id)
 {
     dbgln_if(MATROSKA_DEBUG, "Codec ID: {}", codec_id);
     if (codec_id == "V_VP8")

Libraries/LibMedia/Containers/Matroska/MatroskaDemuxer.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022, Gregory Bertilson <zaggy1024@gmail.com>
+ * Copyright (c) 2022-2025, Gregory Bertilson <gregory@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -54,7 +54,6 @@ class MatroskaDemuxer final : public Demuxer {
     };
 
     DecoderErrorOr<TrackStatus*> get_track_status(Track track);
-    static CodecID get_codec_id_for_string(FlyString const& codec_id);
 
     Reader m_reader;