Implement unicode bidi P2 and P3 rules in BidiResolver

Source/core/platform/text/BidiResolver.h

Index: Source/core/platform/text/BidiResolver.h
diff --git a/Source/core/platform/text/BidiResolver.h b/Source/core/platform/text/BidiResolver.h
index dc5ee34fa25db4ab1b85bc6bc4e7e990f7e2f59f..435612ec3bee7ca6e563d3098f0f080128d7ceb6 100644
--- a/Source/core/platform/text/BidiResolver.h
+++ b/Source/core/platform/text/BidiResolver.h
@@ -223,6 +223,8 @@ public:
 
     bool isEndOfParagraph(const Iterator& end) { return m_current == end || m_current.atEnd(); }
 
+    TextDirection determineParagraphDirectionality(bool* hasStrongDirectionality = 0);
+
 protected:
     void increment() { m_current.increment(); }
     // FIXME: Instead of InlineBidiResolvers subclassing this method, we should
@@ -525,6 +527,36 @@ inline void BidiResolver<Iterator, Run>::reorderRunsFromLevels()
 }
 
 template <class Iterator, class Run>
+TextDirection BidiResolver<Iterator, Run>::determineParagraphDirectionality(bool* hasStrongDirectionality)
+{
+    while (!m_current.atEnd()) {
+        if (inIsolate()) {
+            increment();
+            continue;
+        }
+        if (m_current.atParagraphSeparator())
+            break;
+        if (UChar current = m_current.current()) {
+            WTF::Unicode::Direction charDirection = WTF::Unicode::direction(current);
+            if (charDirection == WTF::Unicode::LeftToRight) {
+                if (hasStrongDirectionality)
+                    *hasStrongDirectionality = true;
+                return LTR;
+            }
+            if (charDirection == WTF::Unicode::RightToLeft || charDirection == WTF::Unicode::RightToLeftArabic) {
+                if (hasStrongDirectionality)
+                    *hasStrongDirectionality = true;
+                return RTL;
+            }
+        }
+        increment();
+    }
+    if (hasStrongDirectionality)
+        *hasStrongDirectionality = false;
+    return LTR;
+}
+
+template <class Iterator, class Run>
 void BidiResolver<Iterator, Run>::createBidiRunsForLine(const Iterator& end, VisualDirectionOverride override, bool hardLineBreak)
 {
     using namespace WTF::Unicode;