Optimize for horizontal writing mode

Source/core/paint/LayerPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/LayerPainter.h"
 
 #include "core/frame/Settings.h"
 #include "core/page/Page.h"
 #include "core/rendering/ClipPathOperation.h"
@@ skipping 642 matching lines @@
                 // Now do a paint with the root layer shifted to be the next multicol block.
                 LayerPaintingInfo columnPaintingInfo(paintingInfo);
                 columnPaintingInfo.rootLayer = columnLayers[colIndex - 1];
                 columnPaintingInfo.paintDirtyRect = transform.inverse().mapRect(localDirtyRect);
                 paintChildLayerIntoColumns(childLayer, context, columnPaintingInfo, paintFlags, columnLayers, colIndex - 1);
             }
         }
 
         // Move to the next position.
         LayoutUnit blockDelta = isHorizontal ? colRect.height() : colRect.width();
-        if (columnBlock->style()->isFlippedBlocksWritingMode())
+        if (columnBlock->style()->slowIsFlippedBlocksWritingMode())
             currLogicalTopOffset += blockDelta;
         else
             currLogicalTopOffset -= blockDelta;
     }
 }
 
 void LayerPainter::paintBackgroundForFragments(const LayerFragments& layerFragments, GraphicsContext* context,
     const LayoutRect& transparencyPaintDirtyRect, bool haveTransparency, const LayerPaintingInfo& localPaintingInfo, PaintBehavior paintBehavior,
     RenderObject* paintingRootForRenderer, PaintLayerFlags paintFlags)
 {
@@ skipping 202 matching lines @@
         if (needsToClip(paintingInfo, clipRect)) {
             clipRecorder = adoptPtr(new ClipRecorder(m_renderLayer.parent(), context, ClipDisplayItem::LayerFragmentParent, clipRect));
             LayerPainter(*m_renderLayer.parent()).applyRoundedRectClips(paintingInfo, context, clipRect, paintFlags, *clipRecorder, DoNotIncludeSelfForBorderRadius); // Child clipping mask painting will handle clipping to self.
         }
 
         paintLayerByApplyingTransform(context, paintingInfo, paintFlags, fragment.paginationOffset);
     }
 }
 
 } // namespace blink