Integrate iframes into the display list
Instead of always promoting iframes to StackingContexts, integrate them
into the display list. This prevents stacking bugs when
non-stacking-context elements should be drawn on top of iframes.
To accomplish this, we add another step to ordering layer creation,
where LayeredItems in the DisplayList are added to layers described by
the LayerInfo structures collected at the end of the DisplayList.
Unlayered items that follow these layered items are added to
synthesized layers.
Another result of this change is that iframe layers can be positioned
directly at the location of the iframe fragment, eliminating the need
for the SubpageLayerInfo struct entirely.
Iframes are the first type of content treated this way, but this change
opens up the possibility to properly order canvas and all other layered
content that does not create a stacking context.
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Add support for `pre-wrap` and `pre-line` values for `white-space`.
This is mostly straightforward. I had to modify a couple of places
which were accidentally discarding whitespace.
Fixes#1513.
This fixes some relevant tests from the CSS testsuite... but a lot of
them are either manual, or don't pass because of unrelated issues. (For
example, white-space-mixed-002 renders correctly, but
white-space-mixed-002-ref doesn't because of a float bug.)
I'd appreciate any suggestions for how to go about adding tests for this.
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Instead of always promoting iframes to StackingContexts, integrate them
into the display list. This prevents stacking bugs when
non-stacking-context elements should be drawn on top of iframes.
To accomplish this, we add another step to ordering layer creation,
where LayeredItems in the DisplayList are added to layers described by
the LayerInfo structures collected at the end of the DisplayList.
Unlayered items that follow these layered items are added to
synthesized layers.
Another result of this change is that iframe layers can be positioned
directly at the location of the iframe fragment, eliminating the need
for the SubpageLayerInfo struct entirely.
Iframes are the first type of content treated this way, but this change
opens up the possibility to properly order canvas and all other layered
content that does not create a stacking context.
Fixes#7566.
Fixes#7796.
Fix iframes flickering on mouse move.
Fixes#7867 (and probably several other iframe bugs).
When collecting layers for children of a pipeline, pass through the current
subpage pipeline recursively. This prevents descendant layers (such as scroll
layers) from being collected and re-created on the subsequent paint.
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