Cherry-pick b8f448e. rdar://122663646

    [IFC][Ruby] Failure to line break before/between ruby sequences
    https://bugs.webkit.org/show_bug.cgi?id=271209
    <rdar://122663646>

    Reviewed by Antti Koivisto.

    Not all "do not break before" characters have "do not break after" meaning. (e.g. no line should begin with KATAKANA MIDDLE DOT but it's ok to have it at the end of the line).
    Let's divide them into 2 categories as seen in https://www.w3.org/TR/jlreq.

    *LayoutTests/fast/ruby/ruby-with-unbreakable-characters-incorrect-width.html: use different punctuation to force line breaking at the right position.
    * LayoutTests/fast/ruby/can-break-before-after-expected.html: Added.
    * LayoutTests/fast/ruby/can-break-before-after.html: Added.
    * Source/WebCore/layout/formattingContexts/inline/ruby/RubyFormattingContext.cpp:
    (WebCore::Layout::canBreakBefore):
    (WebCore::Layout::canBreakAfter):
    (WebCore::Layout::RubyFormattingContext::isAtSoftWrapOpportunity):
    (WebCore::Layout::canBreakAtCharacter): Deleted.

    Canonical link: https://commits.webkit.org/276353@main

Identifier: 272448.821@safari-7618-branch

LayoutTests/fast/ruby/can-break-before-after-expected.html

@@ -0,0 +1,12 @@
+<meta charset="utf8">
+<style>
+div {
+  font-family: Ahem;
+  text-align-last: justify;
+  font-size: 20px;
+  width: 380px;
+}
+</style>
+<div>X X X X ・<ruby>b a s e</ruby>・</div>
+<div><ruby>b a s e</ruby></div>
+<pre>PASS if ・ is not at the start of 'base...' line</pre>

LayoutTests/fast/ruby/can-break-before-after.html

@@ -0,0 +1,11 @@
+<meta charset="utf8">
+<style>
+div {
+  font-family: Ahem;
+  text-align: justify;
+  font-size: 20px;
+  width: 380px;
+}
+</style>
+<div>X X X X ・<ruby>b a s e</ruby>・<ruby>b a s e</ruby></div>
+<pre>PASS if ・ is not at the start of 'base...' line</pre>

LayoutTests/fast/ruby/ruby-with-unbreakable-characters-incorrect-width.html

@@ -11,4 +11,4 @@
 }
 </style>
 <!-- PASS if all content is inside the green box -->
-<div><ruby>XX<rt>XXXXXX</rt></ruby> <ruby>X<rt>XXX</rt></ruby><ruby>X<rt>XXX</rt></ruby>、<ruby>XXXX</ruby></div>
+<div><ruby>XX<rt>XXXXXX</rt></ruby> <ruby>X<rt>XXX</rt></ruby><ruby>X<rt>XXX</rt></ruby>「<ruby>XXXX</ruby></div>

Source/WebCore/layout/formattingContexts/inline/ruby/RubyFormattingContext.cpp

@@ -113,13 +113,13 @@ static bool annotationOverlapCheck(const InlineDisplay::Box& adjacentDisplayBox,
     return false;
 }
 
-static bool canBreakAtCharacter(UChar character)
+static bool canBreakBefore(UChar character)
 {
     auto lineBreak = (ULineBreak)u_getIntPropertyValue(character, UCHAR_LINE_BREAK);
     // UNICODE LINE BREAKING ALGORITHM
     // http://www.unicode.org/reports/tr14/
     // And Requirements for Japanese Text Layout, 3.1.7 Characters Not Starting a Line
-    // http://www.w3.org/TR/2012/NOTE-jlreq-20120403/#characters_not_starting_a_line
+    // https://www.w3.org/TR/jlreq/#characters_not_starting_a_line
     switch (lineBreak) {
     case U_LB_NONSTARTER:
     case U_LB_CLOSE_PARENTHESIS:
@@ -148,6 +148,33 @@ static bool canBreakAtCharacter(UChar character)
     return true;
 }
 
+static bool canBreakAfter(UChar character)
+{
+    // https://www.w3.org/TR/jlreq/#characters_not_ending_a_line
+    switch (character) {
+    case 0x2018: // LEFT SINGLE QUOTATION MARK
+    case 0x201C: // LEFT DOUBLE QUOTATION MARK
+    case 0x0028: // LEFT PARENTHESIS
+    case 0x3014: // LEFT TORTOISE SHELL BRACKET
+    case 0x005B: // LEFT SQUARE BRACKET
+    case 0x007B: // LEFT CURLY BRACKET
+    case 0x3008: // LEFT ANGLE BRACKET
+    case 0x300A: // LEFT DOUBLE ANGLE BRACKET
+    case 0x300C: // LEFT CORNER BRACKET
+    case 0x300E: // LEFT WHITE CORNER BRACKET
+    case 0x3010: // LEFT BLACK LENTICULAR BRACKET
+    case 0x2985: // LEFT WHITE PARENTHESIS
+    case 0x3018: // LEFT WHITE TORTOISE SHELL BRACKET
+    case 0x3016: // LEFT WHITE LENTICULAR BRACKET
+    case 0x00AB: // LEFT-POINTING DOUBLE ANGLE QUOTATION MARK
+    case 0x301D: // REVERSED DOUBLE PRIME QUOTATION MARK
+        return false;
+    default:
+        break;
+    }
+    return true;
+}
+
 bool RubyFormattingContext::isAtSoftWrapOpportunity(const InlineItem& previous, const InlineItem& current)
 {
     auto& previousLayoutBox = previous.layoutBox();
@@ -167,7 +194,7 @@ bool RubyFormattingContext::isAtSoftWrapOpportunity(const InlineItem& previous,
                 return true;
             }
             auto lastCharacter = leadingTextItem.inlineTextBox().content()[leadingTextItem.end() - 1];
-            return canBreakAtCharacter(lastCharacter);
+            return canBreakAfter(lastCharacter);
         }
         // Don't break between base end and <ruby> end.
         return false;
@@ -191,7 +218,7 @@ bool RubyFormattingContext::isAtSoftWrapOpportunity(const InlineItem& previous,
                 return true;
             }
             auto firstCharacter = trailingTextItem.inlineTextBox().content()[trailingTextItem.start()];
-            return canBreakAtCharacter(firstCharacter);
+            return canBreakBefore(firstCharacter);
         }
         // We should handled this case already when looking at current: base, previous: ruby.
         ASSERT_NOT_REACHED();