Bug 25558 – Rendering fix for <select> elements.

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Adam Langley]

Rendering fix for <select> elements.

When switching a <select> element from display:none to default
display, we would fail to invalidate the parent's pref widths in some
situations:

When attaching the element, RenderMenuList::updateOptionsWidth would
call setNeedsLayoutAndPrefWidthsRecalc before the parent pointer was
set. This would mark the pref widths as dirty, but not for any parent
objects.

When RenderObjectChildList::appendChildNode later calls
setNeedsLayoutAndPrefWidthsRecalc again, with a valid parent pointer,
nothing would be done because the pref widths were already dirty for
the RenderMenuList.

Without this patch, the <select> element will spill outside of the
table in the layout test.

This issue was often hidden because, depending on whitespace,
the presence of <option> elements etc, there would often be an empty
RenderText node after the <select> element. This could do the job of
invalidating the parent's pref widths. It's only when this element
isn't present that the bug bites.

[Adam Langley]

Created attachment 30007 [details]
patch

[Darin Adler]

Comment on attachment 30007 [details]
patch

Looks fine, r=me

[Eric Seidel (no email)]

Committing to http://svn.webkit.org/repository/webkit/trunk ...
	M	LayoutTests/ChangeLog
	A	LayoutTests/fast/forms/select-dirty-parent-pref-widths.html
	A	LayoutTests/platform/mac/fast/forms/select-dirty-parent-pref-widths-expected.checksum
	A	LayoutTests/platform/mac/fast/forms/select-dirty-parent-pref-widths-expected.txt
	M	WebCore/ChangeLog
	M	WebCore/rendering/RenderMenuList.cpp
Committed r43278