Ensure clean layout before calling TextIterator::rangeLength in editing code

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

 /*
  * Copyright (C) 2005, 2006, 2007, 2008 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 1281 matching lines @@
         VisiblePosition visibleStart = endingSelection().visibleStart();
         VisiblePosition visibleEnd = endingSelection().visibleEnd();
 
         bool startAfterParagraph = comparePositions(visibleStart, endOfParagraphToMove) > 0;
         bool endBeforeParagraph = comparePositions(visibleEnd, startOfParagraphToMove) < 0;
 
         if (!startAfterParagraph && !endBeforeParagraph) {
             bool startInParagraph = comparePositions(visibleStart, startOfParagraphToMove) >= 0;
             bool endInParagraph = comparePositions(visibleEnd, endOfParagraphToMove) <= 0;
 
+            // TextIterator::rangeLength requires clean layout.
+            document().updateStyleAndLayoutIgnorePendingStylesheets();
+
             startIndex = 0;
             if (startInParagraph)
                 startIndex = TextIterator::rangeLength(startOfParagraphToMove.toParentAnchoredPosition(), visibleStart.toParentAnchoredPosition(), true);
 
             endIndex = 0;
             if (endInParagraph)
                 endIndex = TextIterator::rangeLength(startOfParagraphToMove.toParentAnchoredPosition(), visibleEnd.toParentAnchoredPosition(), true);
         }
     }
 
@@ skipping 342 matching lines @@
 }
 
 DEFINE_TRACE(CompositeEditCommand)
 {
     visitor->trace(m_commands);
     visitor->trace(m_composition);
     EditCommand::trace(visitor);
 }
 
 } // namespace blink