Unify the task source and task canceller API
To do so, I created a struct `TaskManagement(TaskSource,
TaskCanceller)` and made `*_task_source` return that instead of just
the task source.
Next, I refactored all places in which `task_canceller` by basically
removing them in favour of a previously called `*_task_source`.
I tried to make `task_canceller` a private method in `Window`, with the
hope of enforcing the use of `*_task_source`. However, it's used in
components/script/dom/globalscope.rs:575 in such a way that will make it
harder to avoid. I decided to leave it that way.
It'd be possible to unify `*_task_source` in such a way that we would
have only one method. However, I decided not to do it because one of the
`TaskSource` implementations is special:
`history_traversal_task_source`. Not wanting to over complicate things,
I decided to leave the structure this way.
---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#21154 (github issue number if applicable).
- [x] These changes do not require tests because it's refactoring code that should already be tested.
<!-- 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/21804)
<!-- Reviewable:end -->
Clear refcounted promise before dropping JSRuntime
Not sure if this is the right solution?
I also tried to `impl Drop for LiveDOMReferences` but it's still executed after dropping JSRuntime.
So, maybe we should clear it before dropping the JSRuntime?
cc @jdm @asajeffrey
---
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#21331 .
- [x] There are tests for these changes; the status of `fetch/cross-origin-resource-policy/fetch-in-iframe.html` will be `OK`
<!-- 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/21988)
<!-- Reviewable:end -->
Send>
We don't have `window` for `workers`. So, if we use `global.as_window()`
to get the DOMManipulationTaskSource, it will make worker panic.
Instead, we should get the DOMManipulationTaskSource from each own
thread.
Ref: https://github.com/servo/servo/pull/20755#discussion_r193557746
