Don't coerce pointers to compositor layer mappings to booleans.

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..7f4eaa5a069321ec1ab93e149b9bd60c9c2283b0 100644
--- a/Source/core/rendering/RenderLayer.h
+++ b/Source/core/rendering/RenderLayer.h
@@ -45,6 +45,7 @@
 #ifndef RenderLayer_h
 #define RenderLayer_h
 
+#include "core/rendering/CompositedLayerMappingPtr.h"
 #include "core/rendering/CompositingReasons.h"
 #include "core/rendering/LayerPaintingInfo.h"
 #include "core/rendering/PaintInfo.h"
@@ -347,8 +348,8 @@ public:
 
     // 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.
-    CompositedLayerMapping* compositedLayerMapping() const { return m_compositedLayerMapping.get(); }
-    CompositedLayerMapping* ensureCompositedLayerMapping();
+    CompositedLayerMappingPtr compositedLayerMapping() const { return m_compositedLayerMapping.get(); }
+    CompositedLayerMappingPtr ensureCompositedLayerMapping();
     void clearCompositedLayerMapping(bool layerBeingDestroyed = false);
 
     bool hasCompositedMask() const;