Implement HTMLMediaElement poster attribute
- [X] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22288
- [x] There are tests for these changes
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Implement DOM APIs for ChannelSplitterNode
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Based on #21591. Fixes#21558. I tried to update the expected results for WPT using "./mach update-wpt"; let me know if I got something wrong.
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- [x] These changes fix the second half of #21558
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refactoring with ResourceFetchMetadata
implemented deprecated window.timing functionality
created ResourceTimingListener trait
fixed w3c links in navigation timing
updated include.ini to run resource timing tests on ci
Implement unhandledrejection event
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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#15412
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