Raster display item lists via a visual rect RTree.

third_party/WebKit/Source/core/layout/LayoutObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.cpp b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
index 487a40c172e0987a77e7a545a3f3f9a0090e421e..6e6f63263334aac6957219ba26853c1494802ac3 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.cpp
@@ -1623,10 +1623,13 @@ bool LayoutObject::mapToVisualRectInAncestorSpace(const LayoutBoxModelObject* an
         return true;
 
     if (LayoutObject* parent = this->parent()) {
-        if (parent->isBox() && !toLayoutBox(parent)->mapScrollingContentsRectToBoxSpace(rect, parent == ancestor ? ApplyNonScrollOverflowClip : ApplyOverflowClip, visualRectFlags))
-            return false;
-
-        return parent->mapToVisualRectInAncestorSpace(ancestor, rect, visualRectFlags);
+        if (parent->isBox()) {
+            LayoutBox* parentBox = toLayoutBox(parent);
+            if (!parentBox->mapScrollingContentsRectToBoxSpace(rect, parent == ancestor ? ApplyNonScrollOverflowClip : ApplyOverflowClip, visualRectFlags))
+                return false;
+            parentBox->flipForWritingMode(rect);
+        }
+        parent->mapToVisualRectInAncestorSpace(ancestor, rect, visualRectFlags);
     }
     return true;
 }