Introduce composed tree version of inSameLine()

Source/core/editing/VisibleUnits.cpp

Index: Source/core/editing/VisibleUnits.cpp
diff --git a/Source/core/editing/VisibleUnits.cpp b/Source/core/editing/VisibleUnits.cpp
index 53299dd01f215f8cb0d4d752ebda49434321335b..07248e8d7a9a013279e2684db564fe0c14c894b5 100644
--- a/Source/core/editing/VisibleUnits.cpp
+++ b/Source/core/editing/VisibleUnits.cpp
@@ -1121,6 +1121,11 @@ bool inSameLine(const VisiblePosition& position1, const VisiblePosition& positio
     return inSameLine(position1.toPositionWithAffinity(), position2.toPositionWithAffinity());
 }
 
+bool inSameLine(const VisiblePositionInComposedTree& position1, const VisiblePositionInComposedTree& position2)
+{
+    return inSameLine(position1.toPositionWithAffinity(), position2.toPositionWithAffinity());
+}
+
 bool isStartOfLine(const VisiblePosition& p)
 {
     return p.isNotNull() && p.deepEquivalent() == startOfLine(p).deepEquivalent();