Use a boolean hasCompositedLayerMapping() accessor instead of the pointer

Source/core/rendering/RenderLayer.h

Index: Source/core/rendering/RenderLayer.h
diff --git a/Source/core/rendering/RenderLayer.h b/Source/core/rendering/RenderLayer.h
index d48d8448369f91a96d0105e4565930c5643759d3..c19b2bc272fac77157c5c6df469dba343b420ee1 100644
--- a/Source/core/rendering/RenderLayer.h
+++ b/Source/core/rendering/RenderLayer.h
@@ -345,8 +345,10 @@ public:
 
     CompositingState compositingState() const;
 
-    // NOTE: If you are accessing the CompositedLayerMapping as a boolean condition to determine the state of compositing for this layer,
-    // then you may have incorrect logic. Use compositingState() instead.
+    bool hasCompositedLayerMapping() const { return m_compositedLayerMapping.get(); }
+    // NOTE: If you are accessing the CompositedLayerMapping() as a boolean condition to determine the state of compositing for this layer,
+    // then you may have incorrect logic. Use compositingState() instead, or if you really know you just care about the existence of
+    // compositedLayerMapping versus the compositing state, use hasCompositedLayerMapping() instead.
     CompositedLayerMapping* compositedLayerMapping() const { return m_compositedLayerMapping.get(); }
     CompositedLayerMapping* ensureCompositedLayerMapping();
     void clearCompositedLayerMapping(bool layerBeingDestroyed = false);