Make VisiblePosition::init to not use being constructed object

Source/core/editing/VisiblePosition.h

Index: Source/core/editing/VisiblePosition.h
diff --git a/Source/core/editing/VisiblePosition.h b/Source/core/editing/VisiblePosition.h
index f33771b0f7ce4d41d4e3ea744c714661bcddebe3..7c61ba773a49334ceb14dffa1f665053f3198813 100644
--- a/Source/core/editing/VisiblePosition.h
+++ b/Source/core/editing/VisiblePosition.h
@@ -138,6 +138,9 @@ VisiblePosition startVisiblePosition(const Range*, EAffinity);
 
 Element* enclosingBlockFlowElement(const VisiblePosition&);
 
+Position canonicalPositionOf(const Position&);
+PositionWithAffinity honorEditingBoundaryAtOrBeforeOf(const PositionWithAffinity&, const Position& anchor);
+
 bool isFirstVisiblePositionInNode(const VisiblePosition&, const ContainerNode*);
 bool isLastVisiblePositionInNode(const VisiblePosition&, const ContainerNode*);