fix(player): load method fails to reset the media element

[amtins]

Description

This PR provides a workaround for the load method that fails to reset the media element to its initial state when the VHS is used.

This issue affects all devices using VHS tech to play Dash and HLS. It does not affect the playback of media that does not require VHS, such as mp4 or HLS on Apple devices.

This fix does not cover the case when the load method is called directly from the mediaElement.

Screencast.from.13.05.23.21.00.59.webm

How to reproduce

player.src('https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8');

player.cache_.src;
// "https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8"
player.cache_.source;
// { src: "https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8", type: "application/x-mpegURL" }
player.cache_.sources;
// [{ src: "https://d2zihajmogu5jn.cloudfront.net/bipbop-advanced/bipbop_16x9_variant.m3u8", type: "application/x-mpegURL" }]

player.load();

player.cache_.src;
// "blob:http://localhost:9999/bc47fd5c-f3eb-4be9-8fea-40444743105e"
player.cache_.source
// { src: "blob:http://localhost:9999/bc47fd5c-f3eb-4be9-8fea-40444743105e", type: "" }
player.cache_.sources
//[{ src: "blob:http://localhost:9999/bc47fd5c-f3eb-4be9-8fea-40444743105e", type: "" }]

player.src()
// "blob:http://localhost:9999/bc47fd5c-f3eb-4be9-8fea-40444743105e"

Specific Changes proposed

• load method falls back to the src method when vhs tech is used because the specification requirements are met, see mdn load

Appropriate events will be sent to the media element itself as the load process proceeds:

• If the element is already in the process of loading media, that load process is aborted and the abort event is sent.
• If the element has already been initialized with media, the emptied event is sent.
• If resetting the playback position to the beginning of the media actually changes the playback position (that is, it was not already at the beginning), a timeupdate event is sent.
• Once media has been selected and loading is ready to begin, the loadstart event is delivered.
• From this point onward, events are sent just like any media load.

• add test case

Requirements Checklist

• Feature implemented / Bug fixed
• If necessary, more likely in a feature request than a bug fix
  • Change has been verified in an actual browser (Chrome, Firefox, IE)
  • Unit Tests updated or fixed
  • Docs/guides updated
  • Example created (starter template on JSBin)
• Reviewed by Two Core Contributors

[codecov]

Codecov Report

Merging #8274 (05d02e8) into main (f1558c6) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 05d02e8 differs from pull request most recent head 2df6378. Consider uploading reports for the commit 2df6378 to get more accurate results

@@           Coverage Diff           @@
##             main    #8274   +/-   ##
=======================================
  Coverage   82.36%   82.36%           
=======================================
  Files         112      112           
  Lines        7483     7486    +3     
  Branches     1804     1805    +1     
=======================================
+ Hits         6163     6166    +3     
  Misses       1320     1320           

Impacted Files	Coverage Δ
src/js/player.js	90.29% <100.00%> (+0.01%)	⬆️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more