Optimize for horizontal writing mode

Source/core/rendering/RenderView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 355 matching lines @@
 void RenderView::mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect& rect, const PaintInvalidationState* invalidationState) const
 {
     mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, IsNotFixedPosition, invalidationState);
 }
 
 void RenderView::mapRectToPaintInvalidationBacking(const RenderLayerModelObject* paintInvalidationContainer, LayoutRect& rect, ViewportConstrainedPosition viewportConstraint, const PaintInvalidationState* state) const
 {
     if (document().printing())
         return;
 
-    if (style()->isFlippedBlocksWritingMode()) {
+    if (style()->slowIsFlippedBlocksWritingMode()) {
         // We have to flip by hand since the view's logical height has not been determined.  We
         // can use the viewport width and height.
         if (style()->isHorizontalWritingMode())
             rect.setY(viewHeight() - rect.maxY());
         else
             rect.setX(viewWidth() - rect.maxX());
     }
 
     if (viewportConstraint == IsFixedPosition && m_frameView) {
         rect.move(m_frameView->scrollOffsetForFixedPosition());
@@ skipping 485 matching lines @@
     return viewWidth(IncludeScrollbars) / scale;
 }
 
 double RenderView::layoutViewportHeight() const
 {
     float scale = m_frameView ? m_frameView->frame().pageZoomFactor() : 1;
     return viewHeight(IncludeScrollbars) / scale;
 }
 
 } // namespace blink