Make VisiblePosition constructor to canonicalize a position in composed tree

Source/core/dom/Position.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 1186 matching lines @@
         lastPosition = position;
         position = position.upstream(CanCrossEditingBoundary);
     }
     return position;
 }
 
 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;
         if (canHaveChildrenForEditing(deprecatedNode()) && layoutObject->isLayoutBlockFlow() && hasRenderedNonAnonymousDescendantsWithHeight(layoutObject)) {
             // Try a visually equivalent position with possibly opposite editability. This helps in case |this| is in
             // an editable block but surrounded by non-editable positions. It acts to negate the logic at the beginning
             // of LayoutObject::createVisiblePosition().
             PositionType thisPosition = PositionType(*this);
             PositionType equivalent = downstreamIgnoringEditingBoundaries<typename Strategy::PositionType>(thisPosition);
             if (equivalent == thisPosition) {
@@ skipping 193 matching lines @@
         Node* child = NodeTraversal::childAt(*anchor, pos.computeOffsetInContainerNode());
         if (!child)
             return PositionInComposedTree(anchor, PositionInComposedTree::PositionIsAfterChildren);
         child->updateDistribution();
         return PositionInComposedTree(ComposedTreeTraversal::parent(*child), ComposedTreeTraversal::index(*child), PositionInComposedTree::PositionIsOffsetInAnchor);
     }
 
     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())
         return Position();
 
     Node* anchorNode = position.anchorNode();
 
     switch (position.anchorType()) {
     case PositionInComposedTree::PositionIsAfterChildren:
         // FIXME: When anchorNode is <img>, assertion fails in the constructor.
@@ skipping 104 matching lines @@
 
 void showTree(const blink::Position* pos)
 {
     if (pos)
         pos->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil)\n");
 }
 
 #endif