Implement sequential fallback to float speculation
This shouldn't impact any pages that are already rendering correctly, but it is a very naive implementation of this pass.
---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#13284 and fix#13223
- [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/13401)
<!-- Reviewable:end -->
Simplify the way that stacking contexts are collected. Instead of
passing the StackingContextId down the tree, pass the parent
StackingContext itself. This will allow future patches to get more
information about the parent stacking context (such as location).
Also remove the return value of collect_stacking_contexts, which was
unused.
Separating out `REPOSITION` from `REPAINT` allows us to compute
stacking-context-relative positions without rebuilding the display list.
This saves a lot of time when responding to script-to-layout queries.
sizes if the block formatting contexts have negative margins.
The heuristics that determine how and whether floats flow into the
margins are not valid in that case.
Closes#13299.
Move collapse through margin to the top of block flow
<!-- Please describe your changes on the following line: -->
Based on the spec, a collapse through box should be put on the top edge of the flow. This fixed ~110 reftests
---
<!-- 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#12824 (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- 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/13175)
<!-- Reviewable:end -->
Fix root flow's size at the browser window's size
When `<body>` needs to calculate its size based on `<html>`'s size, that should be the size of the browser window itself.
---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#12802 (github issue number if applicable).
- [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/13051)
<!-- Reviewable:end -->
Fix absolute-flow's auto positioning
<!-- Please describe your changes on the following line: -->
If an absolute positioned flow has no top, bottom, left, right property, its hypothetical box position should be the margin-end of its previous sibling, not the border-end.
---
<!-- 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#12676 (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes
<!-- 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/12873)
<!-- Reviewable:end -->
Implement flexible box layout for row container
<!-- Please describe your changes on the following line: -->
This pull requests implements basic flexible box layout for row container.
It has implemented most basic flexbox features, including grow, shrink, multi-line, *reverse properties, and alignment under `justify-content`, `align-items`, `align-self`, `align-content`.
---
<!-- 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] There are tests for these changes
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
r? @pcwalton
<!-- 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/12330)
<!-- Reviewable:end -->
Iterate over the items, create lines from them, resolve flex lengths
against them, set their inline size and margin lengths, and align them
according to 'justify-content', 'align-content' and 'align-self'.
Previously, the code that called this function was responsible for this.
Some code paths neglected to do it. This moves the damage removal to one
central location.
WebRender.
This happens asynchronously, just as it does in non-WebRender mode.
This functionality is a prerequisite for doing proper display-list-based
hit testing in WebRender, since it moves the scroll offsets into Servo
(and, specifically, into the script thread, enabling iframe event
forwarding) instead of keeping them private to WebRender.
Requires servo/webrender_traits#55 and servo/webrender#277.
Partially addresses #11108.
