[CSS Container Queries] Use element writing mode for unit resolution

https://bugs.webkit.org/show_bug.cgi?id=258722
rdar://111565488

Reviewed by Simon Fraser.

Correct handling for vertical writing mode per w3c/csswg-drafts#6873

* LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/container-units-in-at-container-expected.txt:
* LayoutTests/imported/w3c/web-platform-tests/css/css-contain/container-queries/container-units-selection-expected.txt:
* Source/WebCore/css/CSSPrimitiveValue.cpp:
(WebCore::CSSPrimitiveValue::computeNonCalcLengthDouble):

Resolve logical to to physical axis based on the element writing mode.
Also explicitly fall back to small viewport units to guarantee consistency.

Canonical link: https://commits.webkit.org/265654@main

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

@@ -15,8 +15,8 @@ PASS cqmin unit resolves against appropriate container (vertical writing-mode on
 PASS cqmax unit resolves against appropriate container (vertical writing-mode on subject)
 PASS cqw unit resolves against appropriate container (vertical writing-mode on container)
 PASS cqh unit resolves against appropriate container (vertical writing-mode on container)
-FAIL cqi unit resolves against appropriate container (vertical writing-mode on container) assert_equals: expected "true" but got ""
-FAIL cqb unit resolves against appropriate container (vertical writing-mode on container) assert_equals: expected "true" but got ""
+PASS cqi unit resolves against appropriate container (vertical writing-mode on container)
+PASS cqb unit resolves against appropriate container (vertical writing-mode on container)
 PASS cqmin unit resolves against appropriate container (vertical writing-mode on container)
 PASS cqmax unit resolves against appropriate container (vertical writing-mode on container)
 

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

@@ -1,5 +1,5 @@
 Test
 
 PASS Container units select the proper container
-FAIL Units respond to the writing-mode of the element assert_equals: expected "40px" but got "30px"
+PASS Units respond to the writing-mode of the element
 

Source/WebCore/css/CSSPrimitiveValue.cpp

@@ -777,16 +777,26 @@ double CSSPrimitiveValue::computeUnzoomedNonCalcLengthDouble(CSSUnitType primiti
 
 double CSSPrimitiveValue::computeNonCalcLengthDouble(const CSSToLengthConversionData& conversionData, CSSUnitType primitiveType, double value)
 {
-    auto selectContainerRenderer = [&](CQ::Axis axis) -> const RenderBox* {
+    auto resolveContainerUnit = [&](CQ::Axis physicalAxis) -> std::optional<double> {
+        ASSERT(physicalAxis == CQ::Axis::Width || physicalAxis == CQ::Axis::Height);
+
         conversionData.setUsesContainerUnits();
+
         auto* element = conversionData.elementForContainerUnitResolution();
         if (!element)
-            return nullptr;
+            return { };
+
         // FIXME: Use cached query containers when available.
-        auto* container = Style::ContainerQueryEvaluator::selectContainer(axis, nullString(), *element);
+        auto* container = Style::ContainerQueryEvaluator::selectContainer(physicalAxis, nullString(), *element);
         if (!container)
-            return nullptr;
-        return dynamicDowncast<RenderBox>(container->renderer());
+            return { };
+
+        auto* containerRenderer = dynamicDowncast<RenderBox>(container->renderer());
+        if (!containerRenderer)
+            return { };
+
+        auto widthOrHeight = physicalAxis == CQ::Axis::Width ? containerRenderer->contentWidth() : containerRenderer->contentHeight();
+        return widthOrHeight * value / 100;
     };
 
     switch (primitiveType) {
@@ -904,27 +914,27 @@ double CSSPrimitiveValue::computeNonCalcLengthDouble(const CSSToLengthConversion
         break;
 
     case CSSUnitType::CSS_CQW: {
-        if (auto* containerRenderer = selectContainerRenderer(CQ::Axis::Width))
-            return containerRenderer->contentWidth() * value / 100;
-        return value * conversionData.smallViewportFactor().width();
+        if (auto resolvedValue = resolveContainerUnit(CQ::Axis::Width))
+            return *resolvedValue;
+        return computeNonCalcLengthDouble(conversionData, CSSUnitType::CSS_SVW, value);
     }
 
     case CSSUnitType::CSS_CQH: {
-        if (auto* containerRenderer = selectContainerRenderer(CQ::Axis::Height))
-            return containerRenderer->contentHeight() * value / 100;
-        return value * conversionData.smallViewportFactor().height();
+        if (auto resolvedValue = resolveContainerUnit(CQ::Axis::Height))
+            return *resolvedValue;
+        return computeNonCalcLengthDouble(conversionData, CSSUnitType::CSS_SVH, value);
     }
 
     case CSSUnitType::CSS_CQI: {
-        if (auto* containerRenderer = selectContainerRenderer(CQ::Axis::Inline))
-            return containerRenderer->contentLogicalWidth() * value / 100;
-        return value * lengthOfViewportPhysicalAxisForLogicalAxis(LogicalBoxAxis::Inline, conversionData.smallViewportFactor(), conversionData.rootStyle());
+        if (auto resolvedValue = resolveContainerUnit(conversionData.style()->isHorizontalWritingMode() ? CQ::Axis::Width : CQ::Axis::Height))
+            return *resolvedValue;
+        return computeNonCalcLengthDouble(conversionData, CSSUnitType::CSS_SVI, value);
     }
 
     case CSSUnitType::CSS_CQB: {
-        if (auto* containerRenderer = selectContainerRenderer(CQ::Axis::Block))
-            return containerRenderer->contentLogicalHeight() * value / 100;
-        return value * lengthOfViewportPhysicalAxisForLogicalAxis(LogicalBoxAxis::Block, conversionData.smallViewportFactor(), conversionData.rootStyle());
+        if (auto resolvedValue = resolveContainerUnit(conversionData.style()->isHorizontalWritingMode() ? CQ::Axis::Height : CQ::Axis::Width))
+            return *resolvedValue;
+        return computeNonCalcLengthDouble(conversionData, CSSUnitType::CSS_SVB, value);
     }
 
     case CSSUnitType::CSS_CQMAX: