Introduce composed tree version of directionOfEnclosingBlock()

Source/core/editing/EditingUtilities.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 675 matching lines @@
 {
     return RuntimeEnabledFeatures::userSelectAllEnabled() && node && node->layoutObject() && node->layoutObject()->style()->userSelect() == SELECT_ALL;
 
 }
 
 bool nodeIsUserSelectNone(Node* node)
 {
     return node && node->layoutObject() && !node->layoutObject()->isSelectable();
 }
 
-TextDirection directionOfEnclosingBlock(const Position& position)
+template <typename Strategy>
+TextDirection directionOfEnclosingBlockAlgorithm(const PositionAlgorithm<Strategy>& position)
 {
-    Element* enclosingBlockElement = enclosingBlock(position.computeContainerNode());

[yoichio, 2015/08/28 05:55:23]

enclosingBlock has DOM/InComposition overrides so why do you code just like 
|enclosingBlock(position)| ?

[yosin_UTC9, 2015/08/28 06:22:58]

PS#1 does |enclosingBlock(position)|, however as you said in comment:

enclosingBlock(position.computeContainerNode())
== enclosingBlock(firstPositionInOrBeforeNode(position.computeContainerNode())

So, PS#2 passes
PositionAlgorithm<Strategy>::firstPositionInOrBeforeNode(position.computeContainerNode())

+    Element* enclosingBlockElement = enclosingBlock(PositionAlgorithm<Strategy>::firstPositionInOrBeforeNode(position.computeContainerNode()), CannotCrossEditingBoundary);
     if (!enclosingBlockElement)
         return LTR;
     LayoutObject* layoutObject = enclosingBlockElement->layoutObject();
     return layoutObject ? layoutObject->style()->direction() : LTR;
 }
 
+TextDirection directionOfEnclosingBlock(const Position& position)
+{
+    return directionOfEnclosingBlockAlgorithm<EditingStrategy>(position);
+}
+
+TextDirection directionOfEnclosingBlock(const PositionInComposedTree& position)
+{
+    return directionOfEnclosingBlockAlgorithm<EditingInComposedTreeStrategy>(position);
+}
+
 TextDirection primaryDirectionOf(const Node& node)
 {
     TextDirection primaryDirection = LTR;
     for (const LayoutObject* r = node.layoutObject(); r; r = r->parent()) {
         if (r->isLayoutBlockFlow()) {
             primaryDirection = r->style()->direction();
             break;
         }
     }
 
@@ skipping 881 matching lines @@
     // if the selection starts just before a paragraph break, skip over it
     if (isEndOfParagraph(visiblePosition))
         return mostForwardCaretPosition(visiblePosition.next().deepEquivalent());
 
     // 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 mostForwardCaretPosition(visiblePosition.deepEquivalent());
 }
 
 } // namespace blink