childBackgroundIsKnownToBeOpaqueInRect 3661 Source/core/rendering/RenderLayer.cpp     return childBackgroundIsKnownToBeOpaqueInRect(localRect);
childBackgroundIsKnownToBeOpaqueInRect  637 Source/core/rendering/RenderLayer.h     bool childBackgroundIsKnownToBeOpaqueInRect(const LayoutRect&) const;