Revert of Elements whose contents start with an astral Unicode symbol disappear when CSS `::first-letter` is …

Source/platform/fonts/shaping/HarfBuzzShaper.cpp

Index: Source/platform/fonts/shaping/HarfBuzzShaper.cpp
diff --git a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
index a9de6cdb9864eebfa05e207a4246040f87d5456d..895bb6c77785f5c555e36a190bee8022ab77db0b 100644
--- a/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
+++ b/Source/platform/fonts/shaping/HarfBuzzShaper.cpp
@@ -212,6 +212,27 @@
     return advanceSoFar - initialAdvance;
 }
 
+static inline unsigned countGraphemesInCluster(const UChar* str,
+    unsigned strLength, uint16_t startIndex, uint16_t endIndex)
+{
+    if (startIndex > endIndex) {
+        uint16_t tempIndex = startIndex;
+        startIndex = endIndex;
+        endIndex = tempIndex;
+    }
+    uint16_t length = endIndex - startIndex;
+    ASSERT(static_cast<unsigned>(startIndex + length) <= strLength);
+    TextBreakIterator* cursorPosIterator = cursorMovementIterator(&str[startIndex], length);
+
+    int cursorPos = cursorPosIterator->current();
+    int numGraphemes = -1;
+    while (0 <= cursorPos) {
+        cursorPos = cursorPosIterator->next();
+        numGraphemes++;
+    }
+    return numGraphemes < 0 ? 0 : numGraphemes;
+}
+
 static inline void addEmphasisMark(GlyphBuffer* buffer,
     const GlyphData* emphasisData, FloatPoint glyphCenter,
     float midGlyphOffset)
@@ -289,7 +310,7 @@
             else
                 clusterEnd = isRunEnd ? run->m_startIndex + run->m_numCharacters + runOffset : run->glyphToCharacterIndex(i + 1) + runOffset;
 
-            graphemesInCluster = countCharactersAndGraphemesInCluster(textRun.characters16(), textRun.charactersLength(), clusterStart, clusterEnd).graphemes;
+            graphemesInCluster = countGraphemesInCluster(textRun.characters16(), textRun.charactersLength(), clusterStart, clusterEnd);
             if (!graphemesInCluster || !clusterAdvance)
                 continue;