Add Gecko reftests, which are failing with gfx-hal backend
<!-- Please describe your changes on the following line: -->
Since the focus of the Szeged team will shift to Servo from Gecko, we would like to add some reftests from Gecko which are failing with the gfx-rs backend.
Last year we had pretty good results with Servo css tests: https://github.com/szeged/webrender/issues/173#issuecomment-415373702.
On the Gecko side we had more failing tests, and it would be nice to have a subset of those in Servo, even tough some of them fails on the Servo side.
cc @larsbergstrom @jdm @kvark
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23019)
<!-- Reviewable:end -->
In BC event-loop, only run tasks related to fully-active documents
<!-- Please describe your changes on the following line: -->
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [ ] `./mach build -d` does not report any errors
- [ ] `./mach test-tidy` does not report any errors
- [ ] These changes fix#22792 (GitHub issue number if applicable)
<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22802)
<!-- Reviewable:end -->
Make webgl behave better with session history
This prevents the compositor from animating pages that are not actually visible, so pages using webgl do not needlessly impact the performance of the rest of the browser. Additionally, this fixes a problem that was alluded to in [this code](b5228c098b/src/draw_buffer.rs (L282-L285)), causing Servo to delete arbitrary resources when a GC occurred in content that used three.js.
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22987 and fix#22977 and fix#20934 and fix#20953 and fix#20930 and fix#20950 and fix#20924
- [x] There are tests for these changes
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/23000)
<!-- Reviewable:end -->
Fix replacement logic when navigating nested browsing contexts
These changes also fix a bug where traversing the session history in a nested browsing context did not update the iframe's contentWindow appropriately.
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22996
- [x] There are tests for these changes
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22999)
<!-- Reviewable:end -->
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.
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [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)
<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because ___
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22622)
<!-- Reviewable:end -->
Implement historical returnValue attribute for Event interface
<!-- Please describe your changes on the following line: -->
Implementation of `returnValue` attribute for Event interface.
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#22881 (GitHub issue number if applicable)
<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because ___
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22933)
<!-- Reviewable:end -->
Add optional annotations for initEvent method of Event interface
Added `optional` and default values to parameters `bubbles` and `cancelable` of `initEvent` of `Event`.
I tried to update test results, but there seem to be no differences at all.
I checked similar code where `optional` is used, and there seems to be no special handling in Rust. If that is not the case with this issue, please let me know and I'll commit more follow-ups.
---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22883
<!-- Either: -->
- [x] There are tests for these changes OR
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22917)
<!-- Reviewable:end -->
Implement HTMLMediaElement muted and defaultMuted attributes
<!-- Please describe your changes on the following line: -->
PR for issue #22291
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #22291 (github issue number if applicable).
- [X] There are tests for these changes OR
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22347)
<!-- Reviewable:end -->
Add test for contentDocument behaviour during parsing
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#22503
- [x] There are tests for these changes
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/22841)
<!-- Reviewable:end -->