Audit the use of updateStyleAndLayoutIgnorePendingStylesheets in previous/nextLinePosition

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

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 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 514 matching lines @@
 {
     if (selection->isBaseFirst()) {
         selection->setBase(newStart);
         return;
     }
     selection->setExtent(newStart);
 }
 
 bool SelectionModifier::modify(EAlteration alter, SelectionDirection direction, TextGranularity granularity)
 {
+    // TODO(xiaochengh): The use of updateStyleAndLayoutIgnorePendingStylesheets
+    // needs to be audited.  See http://crbug.com/590369 for more details.
+    frame()->document()->updateStyleAndLayoutIgnorePendingStylesheets();
+
+    DocumentLifecycle::DisallowTransitionScope disallowTransition(frame()->document()->lifecycle());
+
     willBeModified(alter, direction);
 
     bool wasRange = m_selection.isRange();
     VisiblePosition originalStartPosition = m_selection.visibleStart();
     VisiblePosition position;
     switch (direction) {
     case DirectionRight:
         if (alter == FrameSelection::AlterationMove)
             position = modifyMovingRight(granularity);
         else
@@ skipping 84 matching lines @@
         return false;
     y = rect.y() + rect.height() / 2;
     return true;
 }
 
 bool SelectionModifier::modifyWithPageGranularity(EAlteration alter, unsigned verticalDistance, VerticalDirection direction)
 {
     if (!verticalDistance)
         return false;
 
+    DCHECK(!frame()->document()->needsLayoutTreeUpdate());
+    DocumentLifecycle::DisallowTransitionScope disallowTransition(frame()->document()->lifecycle());
+
     willBeModified(alter, direction == FrameSelection::DirectionUp ? DirectionBackward : DirectionForward);
 
     VisiblePosition pos;
     LayoutUnit xPos;
     switch (alter) {
     case FrameSelection::AlterationMove:
         pos = createVisiblePosition(direction == FrameSelection::DirectionUp ? m_selection.start() : m_selection.end(), m_selection.affinity());
         xPos = lineDirectionPointForBlockDirectionNavigation(direction == FrameSelection::DirectionUp ? START : END);
         m_selection.setAffinity(direction == FrameSelection::DirectionUp ? TextAffinity::Upstream : TextAffinity::Downstream);
         break;
@@ skipping 113 matching lines @@
     return x;
 }
 
 DEFINE_TRACE(SelectionModifier)
 {
     visitor->trace(m_frame);
     visitor->trace(m_selection);
 }
 
 } // namespace blink