Make VisiblePosition constructor to canonicalize a position in composed tree

Source/core/dom/Position.cpp

Index: Source/core/dom/Position.cpp
diff --git a/Source/core/dom/Position.cpp b/Source/core/dom/Position.cpp
index 851407716b77748218f4557be5b50b7315d7e118..13fe046a10487a81f3845e649f4e89137a658563 100644
--- a/Source/core/dom/Position.cpp
+++ b/Source/core/dom/Position.cpp
@@ -1204,7 +1204,7 @@ template <typename Strategy>
 void PositionAlgorithm<Strategy>::getInlineBoxAndOffset(EAffinity affinity, TextDirection primaryDirection, InlineBox*& inlineBox, int& caretOffset) const
 {
     caretOffset = deprecatedEditingOffset();
-    LayoutObject* layoutObject = deprecatedNode()->layoutObject();
+    LayoutObject* layoutObject = m_anchorNode->isShadowRoot() ? toShadowRoot(m_anchorNode)->host()->layoutObject() : m_anchorNode->layoutObject();
 
     if (!layoutObject->isText()) {
         inlineBox = 0;
@@ -1418,6 +1418,11 @@ PositionInComposedTree toPositionInComposedTree(const Position& pos)
     return PositionInComposedTree(pos.anchorNode(), static_cast<PositionInComposedTree::AnchorType>(pos.anchorType()));
 }
 
+Position toPositionInDOMTree(const Position& position)
+{
+    return position;
+}
+
 Position toPositionInDOMTree(const PositionInComposedTree& position)
 {
     if (position.isNull())