Add clean layout DCHECK to mostBackwardCaretPosition()

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

 /*
  * Copyright (C) 2005, 2006, 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 1379 matching lines @@
   // If the pushDownStart is at the end of a text node, then this node is not
   // fully selected. Move it to the next deep quivalent position to avoid
   // removing the style from this node. e.g. if pushDownStart was at
   // Position("hello", 5) in <b>hello<div>world</div></b>, we want
   // Position("world", 0) instead.
   Node* pushDownStartContainer = pushDownStart.computeContainerNode();
   if (pushDownStartContainer && pushDownStartContainer->isTextNode() &&
       pushDownStart.computeOffsetInContainerNode() ==
           pushDownStartContainer->maxCharacterOffset())
     pushDownStart = nextVisuallyDistinctCandidate(pushDownStart);
+
+  // TODO(editing-dev): Use of updateStyleAndLayoutIgnorePendingStylesheets
+  // needs to be audited.  See http://crbug.com/590369 for more details.
+  document().updateStyleAndLayoutIgnorePendingStylesheets();
+
   Position pushDownEnd = mostBackwardCaretPosition(end);
   // If pushDownEnd is at the start of a text node, then this node is not fully
   // selected. Move it to the previous deep equivalent position to avoid
   // removing the style from this node.
   Node* pushDownEndContainer = pushDownEnd.computeContainerNode();
   if (pushDownEndContainer && pushDownEndContainer->isTextNode() &&
       !pushDownEnd.computeOffsetInContainerNode())
     pushDownEnd = previousVisuallyDistinctCandidate(pushDownEnd);
 
   pushDownInlineStyleAroundNode(style, pushDownStart.anchorNode(),
@@ skipping 602 matching lines @@
 
 DEFINE_TRACE(ApplyStyleCommand) {
   visitor->trace(m_style);
   visitor->trace(m_start);
   visitor->trace(m_end);
   visitor->trace(m_styledInlineElement);
   CompositeEditCommand::trace(visitor);
 }
 
 }  // namespace blink