Introduce Position::inDocument()

Source/core/editing/InsertListCommand.cpp

 /*
  * Copyright (C) 2006, 2010 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 126 matching lines @@
             bool forceCreateList = !selectionHasListOfType(selection, listTag);
 
             RefPtr<Range> currentSelection = endingSelection().firstRange();
             VisiblePosition startOfCurrentParagraph = startOfSelection;
             while (!inSameParagraph(startOfCurrentParagraph, startOfLastParagraph, CanCrossEditingBoundary)) {
                 // doApply() may operate on and remove the last paragraph of the selection from the document
                 // if it's in the same list item as startOfCurrentParagraph.  Return early to avoid an
                 // infinite loop and because there is no more work to be done.
                 // FIXME(<rdar://problem/5983974>): The endingSelection() may be incorrect here.  Compute
                 // the new location of endOfSelection and use it as the end of the new selection.
-                if (!startOfLastParagraph.deepEquivalent().anchorNode()->inDocument())
+                if (!startOfLastParagraph.deepEquivalent().inDocument())
                     return;
                 setEndingSelection(startOfCurrentParagraph);
 
                 // Save and restore endOfSelection and startOfLastParagraph when necessary
                 // since moveParagraph and movePragraphWithClones can remove nodes.
                 // FIXME: This is an inefficient way to keep selection alive because indexForVisiblePosition walks from
                 // the beginning of the document to the endOfSelection everytime this code is executed.
                 // But not using index is hard because there are so many ways we can lose selection inside doApplyForSingleParagraph.
                 RefPtr<ContainerNode> scope;
                 int indexForEndOfSelection = indexForVisiblePosition(endOfSelection, scope);
@@ skipping 231 matching lines @@
     if (listElement)
         return mergeWithNeighboringLists(listElement);
 
     if (canMergeLists(previousList, nextList))
         mergeIdenticalElements(previousList, nextList);
 
     return listElement;
 }
 
 }