Optimize for horizontal writing mode

Source/core/rendering/RenderLayer.cpp

Index: Source/core/rendering/RenderLayer.cpp
diff --git a/Source/core/rendering/RenderLayer.cpp b/Source/core/rendering/RenderLayer.cpp
index 99e2c5dddab1c8fa92c297fa344fa40f9dda6a6a..06051c9ac04807c3a4d95ec7f79a0fd7ba0b16c6 100644
--- a/Source/core/rendering/RenderLayer.cpp
+++ b/Source/core/rendering/RenderLayer.cpp
@@ -2249,19 +2249,22 @@ LayoutRect RenderLayer::logicalBoundingBox() const
     return result;
 }
 
-LayoutRect RenderLayer::flippedLogicalBoundingBox() const
+static inline LayoutRect flippedLogicalBoundingBox(LayoutRect boundingBox, RenderObject* renderer)

[pdr., 2014/10/21 22:11:26]

I don't understand the purpose of making this a static.

[eae, 2014/10/21 22:21:46]

Allows it to be inlined easier. It is a very hot function.

[pdr., 2014/10/21 22:38:15]

Could we just make this inline then?

 {
-    LayoutRect result = logicalBoundingBox();
-    if (m_renderer->isBox())
-        renderBox()->flipForWritingMode(result);
+    if (!UNLIKELY(renderer->document().hasVerticalWritingMode()))
+        return boundingBox;
+
+    LayoutRect result = boundingBox;
+    if (renderer->isBox())
+        toRenderBox(renderer)->flipForWritingMode(result);
     else
-        m_renderer->containingBlock()->flipForWritingMode(result);
+        renderer->containingBlock()->flipForWritingMode(result);
     return result;
 }
 
 LayoutRect RenderLayer::physicalBoundingBox(const RenderLayer* ancestorLayer, const LayoutPoint* offsetFromRoot) const
 {
-    LayoutRect result = flippedLogicalBoundingBox();
+    LayoutRect result = flippedLogicalBoundingBox(logicalBoundingBox(), renderer());
     if (offsetFromRoot)
         result.moveBy(*offsetFromRoot);
     else
@@ -2274,11 +2277,16 @@ LayoutRect RenderLayer::fragmentsBoundingBox(const RenderLayer* ancestorLayer) c
     if (!enclosingPaginationLayer())
         return physicalBoundingBox(ancestorLayer);
 
-    LayoutRect result = flippedLogicalBoundingBox();
+    LayoutRect result = flippedLogicalBoundingBox(logicalBoundingBox(), renderer());
     convertFromFlowThreadToVisualBoundingBoxInAncestor(this, ancestorLayer, result);
     return result;
 }
 
+LayoutRect RenderLayer::boundingBoxForCompositingOverlapTest() const
+{
+    return overlapBoundsIncludeChildren() ? boundingBoxForCompositing() : flippedLogicalBoundingBox(logicalBoundingBox(), renderer());
+}
+
 static void expandRectForReflectionAndStackingChildren(const RenderLayer* ancestorLayer, RenderLayer::CalculateBoundsOptions options, LayoutRect& result)
 {
     if (ancestorLayer->reflectionInfo() && !ancestorLayer->reflectionInfo()->reflectionLayer()->hasCompositedLayerMapping())