Introduce composed tree version of canonicalPosition() in VisiblePosition

Source/core/editing/htmlediting.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007 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 178 matching lines @@
     Node* node = p.containerNode();
     if (!node)
         return 0;
 
     if (isRenderedHTMLTableElement(node))
         node = node->parentNode();
 
     return node->rootEditableElement(editableType);
 }
 
+Element* editableRootForPosition(const PositionInComposedTree& p, EditableType editableType)
+{
+    return editableRootForPosition(toPositionInDOMTree(p), editableType);
+}
+
 // Finds the enclosing element until which the tree can be split.
 // When a user hits ENTER, he/she won't expect this element to be split into two.
 // You may pass it as the second argument of splitTreeToNode.
 Element* unsplittableElementForPosition(const Position& p)
 {
     // Since enclosingNodeOfType won't search beyond the highest root editable node,
     // this code works even if the closest table cell was outside of the root editable node.
     Element* enclosingCell = toElement(enclosingNodeOfType(p, &isTableCell));
     if (enclosingCell)
         return enclosingCell;
@@ skipping 12 matching lines @@
             return p;
     }
     return PositionType();
 }
 
 Position nextCandidate(const Position& position)
 {
     return nextCandidateAlgorithm<EditingStrategy>(position);
 }
 
+PositionInComposedTree nextCandidate(const PositionInComposedTree& position)
+{
+    return nextCandidateAlgorithm<EditingInComposedTreeStrategy>(position);
+}
+
 Position nextVisuallyDistinctCandidate(const Position& position)
 {
     Position p = position;
     Position downstreamStart = p.downstream();
     while (!p.atEndOfTree()) {
         p = p.next(Character);
         if (p.isCandidate() && p.downstream() != downstreamStart)
             return p;
     }
     return Position();
@@ skipping 10 matching lines @@
             return p;
     }
     return PositionType();
 }
 
 Position previousCandidate(const Position& position)
 {
     return previousCandidateAlgorithm<EditingStrategy>(position);
 }
 
+PositionInComposedTree previousCandidate(const PositionInComposedTree& position)
+{
+    return previousCandidateAlgorithm<EditingInComposedTreeStrategy>(position);
+}
+
 template <typename PositionType>
 PositionType previousVisuallyDistinctCandidateAlgorithm(const PositionType& position)
 {
     PositionType p = position;
     PositionType downstreamStart = p.downstream();
     while (!p.atStartOfTree()) {
         p = p.previous(Character);
         if (p.isCandidate() && p.downstream() != downstreamStart)
             return p;
     }
@@ skipping 937 matching lines @@
     // if the selection starts just before a paragraph break, skip over it
     if (isEndOfParagraph(visiblePosition))
         return visiblePosition.next().deepEquivalent().downstream();
 
     // otherwise, make sure to be at the start of the first selected node,
     // instead of possibly at the end of the last node before the selection
     return visiblePosition.deepEquivalent().downstream();
 }
 
 } // namespace blink