Revert "Make compositingState explicit (re-land #2 with bogus ASSERT removed)"

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 2c8cb946a98b18544bcdf8a087f1d2d2d99bd4b4..d3392ebc71cbc3949a00022ebbd8df31da94a835 100644
--- a/Source/core/rendering/RenderLayer.h
+++ b/Source/core/rendering/RenderLayer.h
@@ -461,21 +461,14 @@ public:
     // Only safe to call from RenderLayerModelObject::destroyLayer()
     void operator delete(void*);
 
-    CompositingState compositingState() const;
-
-    CompositedLayerMapping* compositedLayerMapping() const
-    {
-        // NOTE: Checking whether backing exists is equivalent to asking if you are in one of these two compositing states.
-        //       If this is why you are using compositedLayerMapping(), consider using compositingState() instead.
-        return m_compositedLayerMapping.get();
-    }
-
-    CompositedLayerMapping* ensureCompositedLayerMapping();
-    void clearCompositedLayerMapping(bool layerBeingDestroyed = false);
     bool adjustForForceCompositedScrollingMode(bool) const;
 
+    bool isComposited() const { return m_compositedLayerMapping; }
     bool hasCompositedMask() const;
     bool hasCompositedClippingMask() const;
+    CompositedLayerMapping* compositedLayerMapping() const { return m_compositedLayerMapping.get(); }
+    CompositedLayerMapping* ensureCompositedLayerMapping();
+    void clearCompositedLayerMapping(bool layerBeingDestroyed = false);
     bool needsCompositedScrolling() const;
     bool needsToBeStackingContainer() const;
 
@@ -488,7 +481,7 @@ public:
 
     bool paintsWithTransparency(PaintBehavior paintBehavior) const
     {
-        return isTransparent() && ((paintBehavior & PaintBehaviorFlattenCompositingLayers) || compositingState() != PaintsIntoOwnBacking);
+        return isTransparent() && ((paintBehavior & PaintBehaviorFlattenCompositingLayers) || !isComposited());
     }
 
     bool paintsWithTransform(PaintBehavior) const;