Ensure valid VisiblePosition input for absoluteCaretBoundsOf

third_party/WebKit/Source/core/editing/commands/DeleteSelectionCommand.cpp

 /*
  * Copyright (C) 2005 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 640 matching lines @@
     // m_downstreamEnd's block has been emptied out by deletion.  There is no content inside of it to
     // move, so just remove it.
     Element* endBlock = enclosingBlock(m_downstreamEnd.anchorNode());
     if (!endBlock || !endBlock->contains(startOfParagraphToMove.deepEquivalent().anchorNode()) || !startOfParagraphToMove.deepEquivalent().anchorNode()) {
         removeNode(enclosingBlock(m_downstreamEnd.anchorNode()), editingState);
         return;
     }
 
     // We need to merge into m_upstreamStart's block, but it's been emptied out and collapsed by deletion.
     if (!mergeDestination.deepEquivalent().anchorNode() || (!mergeDestination.deepEquivalent().anchorNode()->isDescendantOf(enclosingBlock(m_upstreamStart.computeContainerNode())) && (!mergeDestination.deepEquivalent().anchorNode()->hasChildren() || !m_upstreamStart.computeContainerNode()->hasChildren())) || (m_startsAtEmptyLine && mergeDestination.deepEquivalent() != startOfParagraphToMove.deepEquivalent())) {
+        PositionWithAffinity storedStartOfParagraphToMove = startOfParagraphToMove.toPositionWithAffinity();
         insertNodeAt(HTMLBRElement::create(document()), m_upstreamStart, editingState);
         if (editingState->isAborted())
             return;
         mergeDestination = createVisiblePositionDeprecated(m_upstreamStart);
+        startOfParagraphToMove = createVisiblePosition(storedStartOfParagraphToMove);

[yosin_UTC9, 2016/09/28 01:24:06]

Rational of converting VP:
|startOfParagraphToMove| is used as an argument of |absoluteCaretBoundsOf()| at
L692.

     }
 
     if (mergeDestination.deepEquivalent() == startOfParagraphToMove.deepEquivalent())
         return;
 
     VisiblePosition endOfParagraphToMove = endOfParagraphDeprecated(startOfParagraphToMove, CanSkipOverEditingBoundary);
 
     if (mergeDestination.deepEquivalent() == endOfParagraphToMove.deepEquivalent())
         return;
 
@@ skipping 288 matching lines @@
     visitor->trace(m_deleteIntoBlockquoteStyle);
     visitor->trace(m_startRoot);
     visitor->trace(m_endRoot);
     visitor->trace(m_startTableRow);
     visitor->trace(m_endTableRow);
     visitor->trace(m_temporaryPlaceholder);
     CompositeEditCommand::trace(visitor);
 }
 
 } // namespace blink