Introduce composed tree version of lastEditableVisiblePositionBeforePositionInRoot()

Source/core/editing/EditingUtilities.cpp

Index: Source/core/editing/EditingUtilities.cpp
diff --git a/Source/core/editing/EditingUtilities.cpp b/Source/core/editing/EditingUtilities.cpp
index a868d229ac27a07d992f9d91e1e5248136149d7c..31da42bb5fb38ea96321c63c69b8a2b35c20ef64 100644
--- a/Source/core/editing/EditingUtilities.cpp
+++ b/Source/core/editing/EditingUtilities.cpp
@@ -497,6 +497,11 @@ VisiblePosition lastEditableVisiblePositionBeforePositionInRoot(const Position&
     return createVisiblePosition(lastEditablePositionBeforePositionInRoot(position, highestRoot));
 }
 
+VisiblePositionInComposedTree lastEditableVisiblePositionBeforePositionInRoot(const PositionInComposedTree& position, ContainerNode* highestRoot)
+{
+    return createVisiblePosition(lastEditablePositionBeforePositionInRoot(position, highestRoot));
+}
+
 template <typename Strategy>
 PositionAlgorithm<Strategy> lastEditablePositionBeforePositionInRootAlgorithm(const PositionAlgorithm<Strategy>& position, Node* highestRoot)
 {