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

Source/core/rendering/RenderObject.h

Index: Source/core/rendering/RenderObject.h
diff --git a/Source/core/rendering/RenderObject.h b/Source/core/rendering/RenderObject.h
index 366c887b1172f326301157eaf6d0146b89515004..8a20726e1aed5e4fc5984067d2aedc14de8bfe39 100644
--- a/Source/core/rendering/RenderObject.h
+++ b/Source/core/rendering/RenderObject.h
@@ -30,7 +30,6 @@
 #include "core/dom/Position.h"
 #include "core/dom/StyleEngine.h"
 #include "core/fetch/ImageResourceClient.h"
-#include "core/rendering/CompositingState.h"
 #include "core/rendering/LayoutIndicator.h"
 #include "core/rendering/PaintPhase.h"
 #include "core/rendering/RenderObjectChildList.h"
@@ -701,7 +700,7 @@ public:
     virtual void addAnnotatedRegions(Vector<AnnotatedRegionValue>&);
     void collectAnnotatedRegions(Vector<AnnotatedRegionValue>&);
 
-    CompositingState compositingState() const;
+    bool isComposited() const;
 
     bool hitTest(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestFilter = HitTestAll);
     virtual void updateHitTestResult(HitTestResult&, const LayoutPoint&);