[LFC][Quirk] Use non-collapsed vertical margin values when the container is stretched to the size of the ICB.

[zalan]

ssia

[zalan]

Created attachment 355877 [details]
Patch

[Antti Koivisto]

Comment on attachment 355877 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=355877&action=review

> Source/WebCore/layout/blockformatting/BlockFormattingContextGeometry.cpp:67
>  static HeightAndMargin stretchHeightToInitialContainingBlock(HeightAndMargin heightAndMargin, LayoutUnit initialContainingBlockHeight)
>  {
> -    auto verticalMargins = heightAndMargin.margin.top + heightAndMargin.margin.bottom;
> +    // This quirk happens when the body height is 0 which means its vertical margins collapse through (top and bottom margins are adjoining).
> +    // However now that we stretch the body they don't collapse through anymore, so we need to use the non-collapsed values instead.
> +    ASSERT(initialContainingBlockHeight);
> +    auto verticalMargins = heightAndMargin.height ? heightAndMargin.usedMarginValues() : heightAndMargin.margin;
> +    auto totalVerticalMargins = verticalMargins.top + verticalMargins.bottom;

Could we factor all quirk mode code to a class or namespace or something that says "quirk"?

[zalan]

Committed r238613: <https://trac.webkit.org/changeset/238613>

[Radar WebKit Bug Importer]

<rdar://problem/46311589>