Build fix for Debian Stable after 265057@main https://bugs.webkit.org…

…/show_bug.cgi?id=257931

Reviewed by Myles C. Maxfield.

Attempt to visit an inherited variant results into a compiler error in libstdc++-10.
See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90943

Refactor code to work around compiler error.

* Source/WebCore/css/CSSWordBoundaryDetectionValue.cpp:
(WebCore::CSSWordBoundaryDetectionValue::customCSSText const):
* Source/WebCore/layout/formattingContexts/inline/text/TextUtil.cpp:
(WebCore::Layout::TextUtil::contentAnalysis):
* Source/WebCore/rendering/RenderText.cpp:
(WebCore::mapWordBoundaryDetectionToContentAnalysis):
* Source/WebCore/rendering/style/WordBoundaryDetection.h:
(WebCore::operator<<):

Canonical link: https://commits.webkit.org/265109@main

Source/WebCore/css/CSSWordBoundaryDetectionValue.cpp

@@ -40,7 +40,8 @@ CSSWordBoundaryDetectionValue::CSSWordBoundaryDetectionValue(WordBoundaryDetecti
 String CSSWordBoundaryDetectionValue::customCSSText() const
 {
     TextStream ts;
-    WTF::switchOn(value(), [&ts](WordBoundaryDetectionNormal) {
+    // FIXME: Explicit static_cast to work around issue on libstdc++-10. Undo when upgrading GCC from 10 to 11.
+    WTF::switchOn(static_cast<WordBoundaryDetectionType>(value()), [&ts](WordBoundaryDetectionNormal) {
         ts << "normal";
     }, [&ts](WordBoundaryDetectionManual) {
         ts << "manual";

Source/WebCore/layout/formattingContexts/inline/text/TextUtil.cpp

@@ -375,7 +375,8 @@ TextBreakIterator::LineMode::Behavior TextUtil::lineBreakIteratorMode(LineBreak
 
 TextBreakIterator::ContentAnalysis TextUtil::contentAnalysis(const WordBoundaryDetection& wordBoundaryDetection)
 {
-    return WTF::switchOn(wordBoundaryDetection, [](WordBoundaryDetectionNormal) {
+    // FIXME: Explicit static_cast to work around issue on libstdc++-10. Undo when upgrading GCC from 10 to 11.
+    return WTF::switchOn(static_cast<WordBoundaryDetectionType>(wordBoundaryDetection), [](WordBoundaryDetectionNormal) {
         return TextBreakIterator::ContentAnalysis::Mechanical;
     }, [](WordBoundaryDetectionManual) {
         return TextBreakIterator::ContentAnalysis::Mechanical;

Source/WebCore/rendering/RenderText.cpp

@@ -1041,7 +1041,8 @@ TextBreakIterator::LineMode::Behavior mapLineBreakToIteratorMode(LineBreak lineB
 
 TextBreakIterator::ContentAnalysis mapWordBoundaryDetectionToContentAnalysis(const WordBoundaryDetection& wordBoundaryDetection)
 {
-    return WTF::switchOn(wordBoundaryDetection, [](WordBoundaryDetectionNormal) {
+    // FIXME: Explicit static_cast to work around issue on libstdc++-10. Undo when upgrading GCC from 10 to 11.
+    return WTF::switchOn(static_cast<WordBoundaryDetectionType>(wordBoundaryDetection), [](WordBoundaryDetectionNormal) {
         return TextBreakIterator::ContentAnalysis::Mechanical;
     }, [](WordBoundaryDetectionManual) {
         return TextBreakIterator::ContentAnalysis::Mechanical;

Source/WebCore/rendering/style/WordBoundaryDetection.h

@@ -48,9 +48,12 @@ class WordBoundaryDetection : public std::variant<WordBoundaryDetectionNormal, W
     bool operator==(const WordBoundaryDetection&) const = default;
 };
 
+typedef std::variant<WordBoundaryDetectionNormal, WordBoundaryDetectionManual, WordBoundaryDetectionAuto> WordBoundaryDetectionType;
+
 inline WTF::TextStream& operator<<(TextStream& ts, WordBoundaryDetection wordBoundaryDetection)
 {
-    WTF::switchOn(wordBoundaryDetection, [&ts](WordBoundaryDetectionNormal) {
+    // FIXME: Explicit static_cast to work around issue on libstdc++-10. Undo when upgrading GCC from 10 to 11.
+    WTF::switchOn(static_cast<WordBoundaryDetectionType>(wordBoundaryDetection), [&ts](WordBoundaryDetectionNormal) {
         ts << "normal";
     }, [&ts](WordBoundaryDetectionManual) {
         ts << "manual";