Account for writing-mode flip of the composited element for interest rects.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index d41aef293f0b95ce9767c1ba7c63729d3dc381f2..8afe09c5ceb2f5c4d80bdcf68de62757304f801a 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -2256,6 +2256,9 @@ IntRect CompositedLayerMapping::recomputeInterestRect(const GraphicsLayer* graph
     // Start with the bounds of the graphics layer in the space of the anchor LayoutObject.
     FloatRect graphicsLayerBoundsInObjectSpace(graphicsLayerBounds);
     graphicsLayerBoundsInObjectSpace.move(offsetFromAnchorLayoutObject);
+    // The object space means including writing mode flip.
+    if (anchorLayoutObject->isBox())
+        toLayoutBox(anchorLayoutObject)->flipForWritingMode(graphicsLayerBoundsInObjectSpace);
 
     // Now map the bounds to its visible content rect in screen space, including applying clips along the way.
     LayoutRect visibleContentRect(graphicsLayerBoundsInObjectSpace);