[CSS Container Queries] rem units don't work in queries

https://bugs.webkit.org/show_bug.cgi?id=241852

Reviewed by Antoine Quint.

* LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/font-relative-units-dynamic-expected.txt:
* LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/font-relative-units-expected.txt:
* Source/WebCore/style/ContainerQueryEvaluator.cpp:
(WebCore::Style::ContainerQueryEvaluator::selectContainer const):

Correctly pass the document element style instead of the view style.

Canonical link: https://commits.webkit.org/251734@main
git-svn-id: https://svn.webkit.org/repository/webkit/trunk@295729 268f45cc-cd09-0410-ab3c-d52691b4dbfc

LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/font-relative-units-dynamic-expected.txt

@@ -4,7 +4,7 @@ PASS rem relative before change
 PASS ex relative before change
 PASS ch relative before change
 PASS em relative after change
-FAIL rem relative after change assert_equals: expected "rgb(0, 128, 0)" but got "rgb(255, 0, 0)"
+PASS rem relative after change
 PASS ex relative after change
 PASS ch relative after change
 

LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/font-relative-units-expected.txt

@@ -1,6 +1,6 @@
 
 PASS em relative inline-size
-FAIL rem relative inline-size assert_equals: expected "rgb(0, 128, 0)" but got "rgb(0, 0, 0)"
+PASS rem relative inline-size
 PASS ex relative inline-size
 PASS ch relative inline-size
 

Source/WebCore/style/ContainerQueryEvaluator.cpp

@@ -73,10 +73,9 @@ auto ContainerQueryEvaluator::selectContainer(const FilteredContainerQuery& filt
         auto* renderer = dynamicDowncast<RenderBox>(element.renderer());
         if (!renderer)
             return { };
-        auto& view = renderer->view();
         return {
             renderer,
-            CSSToLengthConversionData { renderer->style(), &view.style(), nullptr, &view }
+            CSSToLengthConversionData { renderer->style(), element.document().documentElement()->renderStyle(), nullptr, &renderer->view() }
         };
     };