Attempt to display inline video fails with Unsupported property declaration: '1280', OtherInvalidValue("width") etc #31208
Description
Servo built from current main
Attempting to load page with embedded MPEG-4 h264 video. Previously this was able to be loaded circa 2021 using layout-2013. Page loads, audio plays, but video does not display. It appears that the video frame size is correctly read from the video track, but script::dom::window reports Unsupported property declaration: '1280', OtherInvalidValue("width") and similarly for height.
./mach run --dev https://au.gmented.com/p/video/test.html
[...]
[2024-01-29T07:23:03Z INFO net::http_loader] GET request for http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/TearsOfSteel.mp4
[2024-01-29T07:23:03Z WARN webrender::device::gl] Attribute VertexAttribute { name: "aUvRect1", count: 4, kind: F32 } is not found in the shader composite. Expected at 6, found at -1
[2024-01-29T07:23:03Z WARN webrender::device::gl] Attribute VertexAttribute { name: "aUvRect2", count: 4, kind: F32 } is not found in the shader composite. Expected at 7, found at -1
[2024-01-29T07:23:03Z INFO net::http_loader] got 206 response for "http://commondatastorage.googleapis.com/... (e4f08cb8a989c71c)"
[2024-01-29T07:23:04Z INFO script::dom::bindings::refcounted] growing refcounted references by 7
[2024-01-29T07:23:04Z INFO script::dom::bindings::refcounted] removing 5 refcounted references
[2024-01-29T07:23:04Z INFO script::dom::window] Url: https://au.gmented.com/p/video/test.html
0:1 Unsupported property declaration: '534', OtherInvalidValue("height")
[2024-01-29T07:23:04Z INFO script::dom::window] Url: https://au.gmented.com/p/video/test.html
0:1 Unsupported property declaration: '1280', OtherInvalidValue("width")
OS: mac OS 14.1.1 on Apple M2 Max (ARM AArch64).
Similar results on Windows 10 on Intel x86_64.