Make previousLinePosition() not to use dangling RootInlineBox

third_party/WebKit/Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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 1310 matching lines @@
             RenderedPosition renderedPosition((createVisiblePosition(position)));
             root = renderedPosition.rootBox();
             if (!root)
                 return createVisiblePosition(position);
         }
     }
 
     if (root) {
         // FIXME: Can be wrong for multi-column layout and with transforms.
         LayoutPoint pointInLine = absoluteLineDirectionPointToLocalPointInBlock(root, lineDirectionPoint);
-        LineLayoutItem lineLayoutItem = root->closestLeafChildForPoint(pointInLine, isEditablePosition(p))->getLineLayoutItem();
+        LineLayoutItem lineLayoutItem = root->closestLeafChildForPoint(pointInLine, isEditablePosition(p, ContentIsEditable, DoNotUpdateStyle))->getLineLayoutItem();
         Node* node = lineLayoutItem.node();
         if (node && editingIgnoresContent(node))
             return createVisiblePosition(Position::inParentBeforeNode(*node));
         return createVisiblePosition(lineLayoutItem.positionForPoint(pointInLine));
     }
 
     // Could not find a previous line. This means we must already be on the first line.
     // Move to the start of the content in this block, which effectively moves us
     // to the start of the line we're on.
     Element* rootElement = node->hasEditableStyle(editableType) ? node->rootEditableElement(editableType) : node->document().documentElement();
@@ skipping 1909 matching lines @@
 {
     return previousPositionOfAlgorithm<EditingStrategy>(visiblePosition, rule);
 }
 
 VisiblePositionInFlatTree previousPositionOf(const VisiblePositionInFlatTree& visiblePosition, EditingBoundaryCrossingRule rule)
 {
     return previousPositionOfAlgorithm<EditingInFlatTreeStrategy>(visiblePosition, rule);
 }
 
 } // namespace blink