Optimize for horizontal writing mode

Source/core/rendering/RenderBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 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.
  *
@@ skipping 519 matching lines @@
     bool isDeprecatedFlexItem() const { return !isInline() && !isFloatingOrOutOfFlowPositioned() && parent() && parent()->isDeprecatedFlexibleBox(); }
     bool isFlexItemIncludingDeprecated() const { return !isInline() && !isFloatingOrOutOfFlowPositioned() && parent() && parent()->isFlexibleBoxIncludingDeprecated(); }
 
     virtual LayoutUnit lineHeight(bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
     virtual int baselinePosition(FontBaseline, bool firstLine, LineDirectionMode, LinePositionMode = PositionOnContainingLine) const override;
 
     virtual LayoutUnit offsetLeft() const override;
     virtual LayoutUnit offsetTop() const override;
 
     LayoutPoint flipForWritingModeForChild(const RenderBox* child, const LayoutPoint&) const;
-    LayoutUnit flipForWritingMode(LayoutUnit position) const; // The offset is in the block direction (y for horizontal writing modes, x for vertical writing modes).
-    LayoutPoint flipForWritingMode(const LayoutPoint&) const;
+    LayoutUnit flipForWritingMode(LayoutUnit position) const

[leviw_travelin_and_unemployed, 2014/10/21 23:30:00]

I'm curious how much of this win is simply due to this inlining. Seems like that
alone could make a big difference.

+    {
+        // The offset is in the block direction (y for horizontal writing modes, x for vertical writing modes).
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return position;
+        return logicalHeight() - position;
+    }
+    LayoutPoint flipForWritingMode(const LayoutPoint& position) const
+    {
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return position;
+        return isHorizontalWritingMode() ? LayoutPoint(position.x(), height() - position.y()) : LayoutPoint(width() - position.x(), position.y());
+    }
     LayoutPoint flipForWritingModeIncludingColumns(const LayoutPoint&) const;
-    LayoutSize flipForWritingMode(const LayoutSize&) const;
-    void flipForWritingMode(LayoutRect&) const;
-    FloatPoint flipForWritingMode(const FloatPoint&) const;
-    void flipForWritingMode(FloatRect&) const;
+    LayoutSize flipForWritingMode(const LayoutSize& offset) const
+    {
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return offset;
+        return isHorizontalWritingMode() ? LayoutSize(offset.width(), height() - offset.height()) : LayoutSize(width() - offset.width(), offset.height());
+    }
+    void flipForWritingMode(LayoutRect& rect) const
+    {
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return;
+        if (isHorizontalWritingMode())
+            rect.setY(height() - rect.maxY());
+        else
+            rect.setX(width() - rect.maxX());
+    }
+    FloatPoint flipForWritingMode(const FloatPoint& position) const
+    {
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return position;
+        return isHorizontalWritingMode() ? FloatPoint(position.x(), height() - position.y()) : FloatPoint(width() - position.x(), position.y());
+    }
+    void flipForWritingMode(FloatRect& rect) const
+    {
+        if (!UNLIKELY(hasFlippedBlocksWritingMode()))
+            return;
+        if (isHorizontalWritingMode())
+            rect.setY(height() - rect.maxY());
+        else
+            rect.setX(width() - rect.maxX());
+    }
     // These represent your location relative to your container as a physical offset.
     // In layout related methods you almost always want the logical location (e.g. x() and y()).
     LayoutPoint topLeftLocation() const;
     LayoutSize topLeftLocationOffset() const;
 
     LayoutRect logicalVisualOverflowRectForPropagation(RenderStyle*) const;
     LayoutRect visualOverflowRectForPropagation(RenderStyle*) const;
     LayoutRect logicalLayoutOverflowRectForPropagation(RenderStyle*) const;
     LayoutRect layoutOverflowRectForPropagation(RenderStyle*) const;
 
@@ skipping 210 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != 0))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // RenderBox_h