Auto merge of #17284 - jyc:custom-properties-cascade, r=emilio

Propagate changes in custom properties' computed values to descendants

If ComputedValues.custom_properties differs between the old and new
ComputedValues, indicate that we have to propogate changes to
descendants by setting child_cascade_requirement to
MustCascadeDescendants in cascade_primary.

style::matching::TElement::cascade_primary already calls
accumulate_damage, which eventually calls
ServoRestyleDamage::compute_style_difference in order to check if other
properties' computed values changed. If any of those change, we signal
that we need to propogate changes for inherited properties.

With Properties & Values, some custom properties will not be inherited,
and we will need to revisit this.

---
<!-- 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 #17283

<!-- 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/17284)
<!-- Reviewable:end -->
This commit is contained in:
bors-servo 2017-06-16 11:04:51 -07:00 committed by GitHub
commit 81275234aa
5 changed files with 57 additions and 2 deletions

View file

@ -66,7 +66,7 @@ pub struct BorrowedSpecifiedValue<'a> {
/// A computed value is just a set of tokens as well, until we resolve variables
/// properly.
#[derive(Clone, Debug)]
#[derive(Clone, Debug, Eq, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
pub struct ComputedValue {
css: String,