Have positionInParentBeforeNode() / positionInParentAfterNode() take a reference

Source/core/editing/IndentOutdentCommand.cpp

Index: Source/core/editing/IndentOutdentCommand.cpp
diff --git a/Source/core/editing/IndentOutdentCommand.cpp b/Source/core/editing/IndentOutdentCommand.cpp
index 13343b2943e3f354c7f27916b8e622ff14349e25..2e5d21633fa89ce9cab23e7f5a59af3e88d03df6 100644
--- a/Source/core/editing/IndentOutdentCommand.cpp
+++ b/Source/core/editing/IndentOutdentCommand.cpp
@@ -118,7 +118,7 @@ void IndentOutdentCommand::indentIntoBlockquote(const Position& start, const Pos
             insertNodeAt(targetBlockquote, start);
         else
             insertNodeBefore(targetBlockquote, outerBlock);
-        startOfContents = VisiblePosition(positionInParentAfterNode(targetBlockquote.get()));
+        startOfContents = VisiblePosition(positionInParentAfterNode(*targetBlockquote));
     }
 
     moveParagraphWithClones(startOfContents, VisiblePosition(end), targetBlockquote.get(), outerBlock.get());