Align criteria for isAlignedForUnder.

https://bugs.webkit.org/show_bug.cgi?id=270431

Reviewed by Alan Baradlay.

The criteria of isAlignedForUnder is not aligned between RenderStyle::changeAffectsVisualOverflow from and isAlignedForUnder in InlineTextBoxStyle.

* LayoutTests/fast/css3-text/css3-text-decoration/text-underline-position/text-underline-position-auto-computed-underline-offset-crash-expected.txt: Added.
* LayoutTests/fast/css3-text/css3-text-decoration/text-underline-position/text-underline-position-auto-computed-underline-offset-crash.html: Added.
* Source/WebCore/rendering/style/RenderStyle.cpp:
(WebCore::RenderStyle::changeAffectsVisualOverflow const):
* Source/WebCore/style/InlineTextBoxStyle.cpp:
(WebCore::isAlignedForUnder):
* Source/WebCore/style/InlineTextBoxStyle.h:

Canonical link: https://commits.webkit.org/275771@main

LayoutTests/fast/css3-text/css3-text-decoration/text-underline-position/text-underline-position-auto-computed-underline-offset-crash-expected.txt

@@ -0,0 +1 @@
+PASS if no crash or assert.

LayoutTests/fast/css3-text/css3-text-decoration/text-underline-position/text-underline-position-auto-computed-underline-offset-crash.html

@@ -0,0 +1,13 @@
+<style>
+    html {
+        writing-mode: vertical-lr;
+    }
+</style>
+<span id=under>PASS</span> if no crash or assert.
+<script>
+    if (window.testRunner)
+        testRunner.dumpAsText();
+    document.body.offsetHeight;
+    under.style.textDecoration = "underline";
+    under.style.textUnderlinePosition = "auto";
+</script>

Source/WebCore/rendering/style/RenderStyle.cpp

@@ -717,10 +717,7 @@ inline bool RenderStyle::changeAffectsVisualOverflow(const RenderStyle& other) c
         || m_rareInheritedData->textUnderlinePosition != other.m_rareInheritedData->textUnderlinePosition) {
         // Underlines are always drawn outside of their textbox bounds when text-underline-position: under;
         // is specified. We can take an early out here.
-        auto isVertialWritingMode = isVerticalWritingMode() || other.isVerticalWritingMode();
-        auto isAlignedForUnder = textUnderlinePosition() == TextUnderlinePosition::Under || other.textUnderlinePosition() == TextUnderlinePosition::Under
-            || (isVertialWritingMode && (textUnderlinePosition() == TextUnderlinePosition::Right || other.textUnderlinePosition() == TextUnderlinePosition::Right || textUnderlinePosition() == TextUnderlinePosition::Left || other.textUnderlinePosition() == TextUnderlinePosition::Left));
-        if (isAlignedForUnder)
+        if (isAlignedForUnder(*this) || isAlignedForUnder(other))
             return true;
         return visualOverflowForDecorations(*this) != visualOverflowForDecorations(other);
     }

Source/WebCore/style/InlineTextBoxStyle.cpp

@@ -42,21 +42,6 @@ struct UnderlineOffsetArguments {
     std::optional<TextUnderlinePositionUnder> textUnderlinePositionUnder { };
 };
 
-static bool isAlignedForUnder(const RenderStyle& decoratingBoxStyle)
-{
-    auto underlinePosition = decoratingBoxStyle.textUnderlinePosition();
-    if (underlinePosition == TextUnderlinePosition::Under)
-        return true;
-    if (decoratingBoxStyle.isHorizontalWritingMode())
-        return false;
-    if (underlinePosition == TextUnderlinePosition::Left || underlinePosition == TextUnderlinePosition::Right) {
-        // In vertical typographic modes, the underline is aligned as for under for 'left' and 'right'.
-        return true;
-    }
-    // When left/right support is not enabled.
-    return underlinePosition == TextUnderlinePosition::Auto && decoratingBoxStyle.textUnderlineOffset().isAuto();
-}
-
 static bool isAncestorAndWithinBlock(const RenderInline& ancestor, const RenderObject* child)
 {
     const RenderObject* object = child;
@@ -279,6 +264,21 @@ static GlyphOverflow computedVisualOverflowForDecorations(const RenderStyle& lin
     return overflowResult;
 }
 
+bool isAlignedForUnder(const RenderStyle& decoratingBoxStyle)
+{
+    auto underlinePosition = decoratingBoxStyle.textUnderlinePosition();
+    if (underlinePosition == TextUnderlinePosition::Under)
+        return true;
+    if (decoratingBoxStyle.isHorizontalWritingMode())
+        return false;
+    if (underlinePosition == TextUnderlinePosition::Left || underlinePosition == TextUnderlinePosition::Right) {
+        // In vertical typographic modes, the underline is aligned as for under for 'left' and 'right'.
+        return true;
+    }
+    // When left/right support is not enabled.
+    return underlinePosition == TextUnderlinePosition::Auto && decoratingBoxStyle.textUnderlineOffset().isAuto();
+}
+
 GlyphOverflow visualOverflowForDecorations(const InlineIterator::LineBoxIterator& lineBox, const RenderText& renderer, float textBoxLogicalTop, float textBoxLogicalBottom)
 {
     auto& style = lineBox->isFirst() ? renderer.firstLineStyle() : renderer.style();

Source/WebCore/style/InlineTextBoxStyle.h

@@ -60,6 +60,7 @@ struct TextUnderlinePositionUnder {
 GlyphOverflow visualOverflowForDecorations(const RenderStyle&);
 GlyphOverflow visualOverflowForDecorations(const RenderStyle&, TextUnderlinePositionUnder);
 GlyphOverflow visualOverflowForDecorations(const InlineIterator::LineBoxIterator&, const RenderText&, float textBoxLogicalTop, float textBoxLogicalBottom);
+bool isAlignedForUnder(const RenderStyle& decoratingBoxStyle);
 
 float underlineOffsetForTextBoxPainting(const InlineIterator::InlineBox&, const RenderStyle&);
 float overlineOffsetForTextBoxPainting(const InlineIterator::InlineBox&, const RenderStyle&);