[video_player_avfoundation] Support the audio-only HLS (.m3u8) on iOS (#7890)

Supports the audio-only HLS on iOS. 

After through flutter/plugins#4639 and flutter/plugins#4727, we can play HLS videos and audios, but it does not support audio-only HLS. When attempting to play that on iOS, it never finishes initialization.

Show the before/after demonstration here: flutter/flutter#156589 (comment)

Fixes: flutter/flutter#156589
Test with flutter/assets-for-api-docs#252

Author: napoleon-na

packages/video_player/video_player_avfoundation/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 2.6.5
+
+* Bugfix to allow the audio-only HLS (.m3u8) on iOS.
+
 ## 2.6.4
 
 * Refactors native code structure.

packages/video_player/video_player_avfoundation/darwin/RunnerTests/VideoPlayerTests.m

@@ -530,6 +530,22 @@ - (void)testHLSControls {
   XCTAssertEqualWithAccuracy([videoInitialization[@"duration"] intValue], 4000, 200);
 }
 
+- (void)testAudioOnlyHLSControls {
+  NSObject<FlutterPluginRegistrar> *registrar =
+      [GetPluginRegistry() registrarForPlugin:@"TestAudioOnlyHLSControls"];
+
+  FVPVideoPlayerPlugin *videoPlayerPlugin =
+      (FVPVideoPlayerPlugin *)[[FVPVideoPlayerPlugin alloc] initWithRegistrar:registrar];
+
+  NSDictionary<NSString *, id> *videoInitialization =
+      [self testPlugin:videoPlayerPlugin
+                   uri:@"https://flutter.github.io/assets-for-api-docs/assets/videos/hls/"
+                       @"bee_audio_only.m3u8"];
+  XCTAssertEqualObjects(videoInitialization[@"height"], @0);
+  XCTAssertEqualObjects(videoInitialization[@"width"], @0);
+  XCTAssertEqualWithAccuracy([videoInitialization[@"duration"] intValue], 4000, 200);
+}
+
 #if TARGET_OS_IOS
 - (void)testTransformFix {
   [self validateTransformFixForOrientation:UIImageOrientationUp];

packages/video_player/video_player_avfoundation/darwin/video_player_avfoundation/Sources/video_player_avfoundation/FVPVideoPlayer.m

@@ -383,7 +383,9 @@ - (void)setupEventSinkIfReadyToPlay {
     }
 
     BOOL hasVideoTracks = [asset tracksWithMediaType:AVMediaTypeVideo].count != 0;
-    BOOL hasNoTracks = asset.tracks.count == 0;
+    // Audio-only HLS files have no size, so `currentItem.tracks.count` must be used to check for
+    // track presence, as AVAsset does not always provide track information in HLS streams.
+    BOOL hasNoTracks = currentItem.tracks.count == 0 && asset.tracks.count == 0;
 
     // The player has not yet initialized when it has no size, unless it is an audio-only track.
     // HLS m3u8 video files never load any tracks, and are also not yet initialized until they have

packages/video_player/video_player_avfoundation/pubspec.yaml

@@ -2,7 +2,7 @@ name: video_player_avfoundation
 description: iOS and macOS implementation of the video_player plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/video_player/video_player_avfoundation
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
-version: 2.6.4
+version: 2.6.5
 
 environment:
   sdk: ^3.3.0