Introduce isRenderedCharacter(Position) function

Source/core/editing/commands/InsertParagraphSeparatorCommand.cpp

 /*
  * Copyright (C) 2005, 2006 Apple Computer, 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 399 matching lines @@
                     break;
             }
         }
 
         moveRemainingSiblingsToNewParent(n, blockToInsert.get(), blockToInsert);
     }
 
     // Handle whitespace that occurs after the split
     if (positionAfterSplit.isNotNull()) {
         document().updateLayoutIgnorePendingStylesheets();
-        if (!positionAfterSplit.isRenderedCharacter()) {
+        // TODO(yosin) |isRenderedCharacter()| should be removed, and we should
+        // use |VisiblePosition::characterAfter()|.
+        if (!isRenderedCharacter(positionAfterSplit)) {
             // Clear out all whitespace and insert one non-breaking space
             ASSERT(!positionAfterSplit.computeContainerNode()->layoutObject() || positionAfterSplit.computeContainerNode()->layoutObject()->style()->collapseWhiteSpace());
             deleteInsignificantTextDownstream(positionAfterSplit);
             if (positionAfterSplit.anchorNode()->isTextNode())
                 insertTextIntoNode(toText(positionAfterSplit.computeContainerNode()), 0, nonBreakingSpaceString());
         }
     }
 
     setEndingSelection(VisibleSelection(firstPositionInNode(blockToInsert.get()), DOWNSTREAM, endingSelection().isDirectional()));
     applyStyleAfterInsertion(startBlock.get());
 }
 
 DEFINE_TRACE(InsertParagraphSeparatorCommand)
 {
     visitor->trace(m_style);
     CompositeEditCommand::trace(visitor);
 }
 
 
 } // namespace blink