Auto merge of #22622 - sreeise:audio_video_tracks, r=jdm

Added AudioTrack, AudioTrackList, VideoTrack, and VideoTrackList inte…

…rfaces

<!-- Please describe your changes on the following line: -->

Added AudioTrack, AudioTrackList, VideoTrack, VideoTrackList, and TrackEvent interfaces to support multiple media tracks.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix #22301  (GitHub issue number if applicable)

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because ___

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components/script/dom/webidls/AudioTrack.webidl

@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#audiotrack
+
+[Exposed=Window]
+interface AudioTrack {
+  readonly attribute DOMString id;
+  readonly attribute DOMString kind;
+  readonly attribute DOMString label;
+  readonly attribute DOMString language;
+  attribute boolean enabled;
+};

components/script/dom/webidls/AudioTrackList.webidl

@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#audiotracklist
+
+[Exposed=Window]
+interface AudioTrackList : EventTarget {
+  readonly attribute unsigned long length;
+  getter AudioTrack (unsigned long index);
+  AudioTrack? getTrackById(DOMString id);
+
+  attribute EventHandler onchange;
+  attribute EventHandler onaddtrack;
+  attribute EventHandler onremovetrack;
+};

components/script/dom/webidls/HTMLMediaElement.webidl

@@ -59,8 +59,8 @@ interface HTMLMediaElement : HTMLElement {
   [CEReactions] attribute boolean defaultMuted;
 
   // tracks
-  // readonly attribute AudioTrackList audioTracks;
-  // readonly attribute VideoTrackList videoTracks;
+  readonly attribute AudioTrackList audioTracks;
+  readonly attribute VideoTrackList videoTracks;
   readonly attribute TextTrackList textTracks;
   TextTrack addTextTrack(TextTrackKind kind, optional DOMString label = "", optional DOMString language = "");
 };

components/script/dom/webidls/TrackEvent.webidl

@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#the-trackevent-interface
+
+[Exposed=Window,
+ Constructor(DOMString type, optional TrackEventInit eventInitDict)]
+interface TrackEvent : Event {
+  readonly attribute (VideoTrack or AudioTrack or TextTrack)? track;
+};
+
+dictionary TrackEventInit : EventInit {
+  (VideoTrack or AudioTrack or TextTrack)? track = null;
+};

components/script/dom/webidls/VideoTrack.webidl

@@ -0,0 +1,14 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#videotrack
+
+[Exposed=Window]
+interface VideoTrack {
+  readonly attribute DOMString id;
+  readonly attribute DOMString kind;
+  readonly attribute DOMString label;
+  readonly attribute DOMString language;
+  attribute boolean selected;
+};

components/script/dom/webidls/VideoTrackList.webidl

@@ -0,0 +1,17 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+// https://html.spec.whatwg.org/multipage/#videotracklist
+
+[Exposed=Window]
+interface VideoTrackList : EventTarget {
+  readonly attribute unsigned long length;
+  getter VideoTrack (unsigned long index);
+  VideoTrack? getTrackById(DOMString id);
+  readonly attribute long selectedIndex;
+
+  attribute EventHandler onchange;
+  attribute EventHandler onaddtrack;
+  attribute EventHandler onremovetrack;
+};