Prevent squashing into your own compositing container

Source/core/rendering/compositing/CompositingLayerAssigner.cpp

Index: Source/core/rendering/compositing/CompositingLayerAssigner.cpp
diff --git a/Source/core/rendering/compositing/CompositingLayerAssigner.cpp b/Source/core/rendering/compositing/CompositingLayerAssigner.cpp
index fc17fafbc047c84ccab494b3e7429e7c64d12646..1c70e6ea95409d916b111284d05e313baa8fbf33 100644
--- a/Source/core/rendering/compositing/CompositingLayerAssigner.cpp
+++ b/Source/core/rendering/compositing/CompositingLayerAssigner.cpp
@@ -133,6 +133,9 @@ bool CompositingLayerAssigner::canSquashIntoCurrentSquashingOwner(const RenderLa
     if (layer->renderer()->clippingContainer() != squashingLayer.renderer()->clippingContainer())
         return false;
 
+    if (layer->compositingContainer() == &squashingLayer)
+        return false;
+
     // Composited descendants need to be clipped by a child contianment graphics layer, which would not be available if the layer is
     if (m_compositor->clipsCompositingDescendants(layer))
         return false;