[web] Don't get break type from v8BreakIterator

lib/web_ui/lib/src/engine/text/line_breaker.dart

@@ -84,8 +84,6 @@ List<LineBreakFragment> breakLinesUsingV8BreakIterator(String text, JSString jsT
   iterator.adoptText(jsText);
   iterator.first();
   while (iterator.next() != -1) {
-    final LineBreakType type = _getV8BreakType(text, iterator);
-
     final int fragmentEnd = iterator.current().toInt();
     int trailingNewlines = 0;
     int trailingSpaces = 0;
@@ -115,6 +113,15 @@ List<LineBreakFragment> breakLinesUsingV8BreakIterator(String text, JSString jsT
       }
     }
 
+    final LineBreakType type;
+    if (trailingNewlines > 0) {
+      type = LineBreakType.mandatory;
+    } else if (fragmentEnd == text.length) {
+      type = LineBreakType.endOfText;
+    } else {
+      type = LineBreakType.opportunity;
+    }
+
     breaks.add(LineBreakFragment(
       fragmentStart,
       fragmentEnd,
@@ -132,20 +139,6 @@ List<LineBreakFragment> breakLinesUsingV8BreakIterator(String text, JSString jsT
   return breaks;
 }
 
-/// Gets break type from v8BreakIterator.
-LineBreakType _getV8BreakType(String text, DomV8BreakIterator iterator) {
-  final int fragmentEnd = iterator.current().toInt();
-
-  // I don't know why v8BreakIterator uses the type "none" to mean "soft break".
-  if (iterator.breakType() != 'none') {
-    return LineBreakType.mandatory;
-  }
-  if (fragmentEnd == text.length) {
-    return LineBreakType.endOfText;
-  }
-  return LineBreakType.opportunity;
-}
-
 class LineBreakFragment extends TextFragment {
   const LineBreakFragment(super.start, super.end, this.type, {
     required this.trailingNewlines,

lib/web_ui/test/html/text/line_breaker_test.dart

@@ -410,6 +410,46 @@ void testMain() {
       }
     });
   });
+
+  group('v8BreakIterator hard line breaks', () {
+    List<Line> split(String text) {
+      return V8LineBreakFragmenter(text)
+          .fragment()
+          .map((LineBreakFragment fragment) => Line.fromLineBreakFragment(text, fragment))
+          .toList();
+    }
+
+    test('thai text with hard line breaks', () {
+      const String thaiText = '\u0E1A\u0E38\u0E1C\u0E25\u0E01\u0E32\u0E23';
+      expect(split(thaiText), <Line>[
+        Line('\u0E1A\u0E38', opportunity),
+        Line('\u0E1C\u0E25', opportunity),
+        Line('\u0E01\u0E32\u0E23', endOfText),
+      ]);
+      expect(split('$thaiText\n'), <Line>[
+        Line('\u0E1A\u0E38', opportunity),
+        Line('\u0E1C\u0E25', opportunity),
+        Line('\u0E01\u0E32\u0E23\n', mandatory, nl: 1, sp: 1),
+        Line('', endOfText),
+      ]);
+    });
+
+    test('khmer text with hard line breaks', () {
+      const String khmerText =
+          '\u179B\u1792\u17D2\u179C\u17BE\u17B2\u17D2\u1799';
+      expect(split(khmerText), <Line>[
+        Line('\u179B', opportunity),
+        Line('\u1792\u17D2\u179C\u17BE', opportunity),
+        Line('\u17B2\u17D2\u1799', endOfText),
+      ]);
+      expect(split('$khmerText\n'), <Line>[
+        Line('\u179B', opportunity),
+        Line('\u1792\u17D2\u179C\u17BE', opportunity),
+        Line('\u17B2\u17D2\u1799\n', mandatory, nl: 1, sp: 1),
+        Line('', endOfText),
+      ]);
+    });
+  }, skip: domIntl.v8BreakIterator == null);
 }
 
 typedef CreateLineBreakFragmenter = LineBreakFragmenter Function(String text);