nsString bindings update
<!-- Please describe your changes on the following line: -->
This fixes bugzilla bug [1403170](https://bugzilla.mozilla.org/show_bug.cgi?id=1403170).
We've missed a few updates of the nsstring bindings in servo compared to the changes in gecko, so we really ought to find a better solution than these manual updates. For example, recently the way flags in nsstring are implemented was completely redone, and this version wasn't updated. It happened to be that the representation of the new form was identical to the old one, so it wasn't a problem, but technically this was wrong.
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build-geckolib` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix bugzilla bug [1403170](https://bugzilla.mozilla.org/show_bug.cgi?id=1403170)
<!-- Either: -->
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because they are a dependency version bump.
<!-- 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/18642)
<!-- Reviewable:end -->
Two small tweaks related to MallocSizeOf
<!-- 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: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because tested on the Gecko side.
<!-- 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/18637)
<!-- Reviewable:end -->
In a later PR, DomRoot<T> will become a type alias of Root<Dom<T>>,
where Root<T> will be able to handle all the things that need to be
rooted that have a stable traceable address that doesn't move for the
whole lifetime of the root. Stay tuned.
I don't want to do such a gratuitous rename, but with all the other types
now having "Dom" as part of their name, and especially with "DomOnceCell",
I feel like the other cell type that we already have should also follow
the convention. That argument loses weight though when we realise there
is still DOMString and other things.
Removed integrity check and test for no-cors requests
Removed Step 30.2 which raised a JS TypeError if the integrity metadata was not empty. I manually ran `new Request("", {"mode" : "no-cors", "integrity" : "not an empty string"});` in servo to validate that the exception no longer arose.
---
<!-- 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#18345
- [x] These changes do not require tests because according to the ticket "Unfortunately, there's no automated test available for this yet because we are having trouble updating our copy of the upstream tests. "
<!-- 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/18617)
<!-- Reviewable:end -->
Make dictionaries and unions containing GC values safer
Problems:
* the Heap::new constructor is memory-unsafe with any value other than Undefined/Null
* this means that moving dictionaries containing Heap values (ie. any/object) is memory-unsafe
* unions containing GC pointers are similarly unsafe
Solutions:
- dictionaries containing GC pointers are now wrapped in RootedTraceableBox (even inside other dictionaries)
- instead of using Heap::new, dictionaries containing GC pointers are now initialized to a default value (by deriving Default) and mutated one field at a time
- dictionaries containing GC pointers are marked #[must_root]
- FromJSVal for dictionaries containing GC pointers now returns RootedTraceableBox<Dictionary>
- unions wrap their variants that require rooting in RootedTraceableBox
Rather than attempting to derive Default for all dictionaries, we only do so for the dictionaries that require it. Because some dictionaries that require it inherit from dictionaries that do not, we need to write manual implementations for those parent dictionaries. This is a better option than having to figure out a default value for types like `Root<T>`, which would be required for deriving Default for all dictionaries.
I would still like to come up with an automated test for this, but I figured I would get eyes on this first.
---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#16952
- [ ] 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/17056)
<!-- Reviewable:end -->
Mark dictionaries containing GC values as must_root, and wrap them in
RootedTraceableBox in automatically-generated APIs. To accommodate
union variants that are now flagged as unsafe, add RootedTraceableBox
to union variants that need to be rooted, rather than wrapping the
entire union value.
Update link to Windows Python Version in README
<!-- Please describe your changes on the following line: -->
The README currently points to a 2 year old version python for windows (2.7.11). While this version works for servo development, builds also work with the current version (2.7.14), so the link can be updated.
---
<!-- 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
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because change is documentation update
<!-- 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/18629)
<!-- Reviewable:end -->
The README currently points to a 2 year old version of
python (2.7.11). While this version works for servo development,
builds also work with the current version (2.7.14), so the link can be
updated.
This matches Gecko, and fixes the last reported case in bug 1397619.
MozReview-Commit-ID: 4Z7GeaokKE1
Signed-off-by: Emilio Cobos Álvarez <emilio@crisal.io>
