::first-letter should include preceding punctuation and space separators

https://bugs.webkit.org/show_bug.cgi?id=179815

Reviewed by NOBODY (OOPS!).

Updating the punctuation categories that are included preceding and following the initial letter
according to https://www.w3.org/TR/css-pseudo-4/#first-letter-pattern.
Additionally adds narrow no-break space to spaces accepted preceding the first-letter,
according to the resolution on w3c/csswg-drafts#9413 (comment)
This change makes first-letter-punctuation-and-space.html pass.

* LayoutTests/TestExpectations:
* Source/WebCore/rendering/updating/RenderTreeBuilderFirstLetter.cpp:
(WebCore::isPrecedingPunctuationForFirstLetter):
(WebCore::isFollowingPunctuationForFirstLetter):
(WebCore::shouldSkipForFirstLetter):
(WebCore::RenderTreeBuilder::FirstLetter::createRenderers):
(WebCore::isPunctuationForFirstLetter): Deleted.

Author: johannesodland

LayoutTests/TestExpectations

@@ -5889,7 +5889,6 @@ webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/active-select
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/active-selection-031.html [ ImageOnlyFailure ]
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/active-selection-057.html [ ImageOnlyFailure ]
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/first-letter-digraph.html [ ImageOnlyFailure ]
-webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/first-letter-punctuation-and-space.html [ ImageOnlyFailure ]
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/first-letter-punctuation-dynamic.html [ ImageOnlyFailure ]
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/first-letter-skip-empty-span-nested.html [ ImageOnlyFailure ]
 webkit.org/b/230004 imported/w3c/web-platform-tests/css/css-pseudo/first-letter-skip-empty-span.html [ ImageOnlyFailure ]

Source/WebCore/rendering/updating/RenderTreeBuilderFirstLetter.cpp

@@ -94,17 +94,23 @@ static std::optional<RenderStyle> styleForFirstLetter(const RenderElement& first
     return firstLetterStyle;
 }
 
-// CSS 2.1 http://www.w3.org/TR/CSS21/selector.html#first-letter
-// "Punctuation (i.e, characters defined in Unicode [UNICODE] in the "open" (Ps), "close" (Pe),
-// "initial" (Pi). "final" (Pf) and "other" (Po) punctuation classes), that precedes or follows the first letter should be included"
-static inline bool isPunctuationForFirstLetter(char32_t c)
+// CSS Pseudo-Elements Module Level 4 https://www.w3.org/TR/css-pseudo-4/#first-letter-pattern
+// "All punctuation—i.e, characters that belong to the Punctuation (P*) Unicode general category [UAX44]—that precedes the first letter."
+static inline bool isPrecedingPunctuationForFirstLetter(char32_t c)
 {
-    return U_GET_GC_MASK(c) & (U_GC_PS_MASK | U_GC_PE_MASK | U_GC_PI_MASK | U_GC_PF_MASK | U_GC_PO_MASK);
+    return U_GET_GC_MASK(c) & (U_GC_PD_MASK | U_GC_PS_MASK | U_GC_PE_MASK | U_GC_PI_MASK | U_GC_PF_MASK | U_GC_PC_MASK | U_GC_PO_MASK);
+}
+
+// "Any punctuation other than opening punctuation and dashes—i.e. characters that belong to the Punctuation (P*) Unicode general category,
+// excluding Open Punctuation (Ps) and Dash Punctuation (Pd)—that follows the first letter."
+static inline bool isFollowingPunctuationForFirstLetter(char32_t c)
+{
+    return U_GET_GC_MASK(c) & (U_GC_PE_MASK | U_GC_PI_MASK | U_GC_PF_MASK | U_GC_PC_MASK | U_GC_PO_MASK);
 }
 
 static inline bool shouldSkipForFirstLetter(char32_t c)
 {
-    return deprecatedIsSpaceOrNewline(c) || c == noBreakSpace || isPunctuationForFirstLetter(c);
+    return deprecatedIsSpaceOrNewline(c) || c == noBreakSpace || c == narrowNoBreakSpace || isPrecedingPunctuationForFirstLetter(c);
 }
 
 static bool supportsFirstLetter(RenderBlock& block)
@@ -260,7 +266,7 @@ void RenderTreeBuilder::FirstLetter::createRenderers(RenderText& currentTextChil
 
             numCodeUnits = numCodeUnitsInGraphemeClusters(StringView(oldText).substring(scanLength), 1);
 
-            if (isPunctuationForFirstLetter(c))
+            if (isFollowingPunctuationForFirstLetter(c))
                 length = scanLength + numCodeUnits;
         }