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

Source/web/LinkHighlight.cpp

Index: Source/web/LinkHighlight.cpp
diff --git a/Source/web/LinkHighlight.cpp b/Source/web/LinkHighlight.cpp
index f0610b6c610d491f321a62892eb5b27031154caa..ec48689d702a578f67b23fd96f62fa4091dd6a41 100644
--- a/Source/web/LinkHighlight.cpp
+++ b/Source/web/LinkHighlight.cpp
@@ -123,7 +123,7 @@ RenderLayer* LinkHighlight::computeEnclosingCompositingLayer()
     } while (!repaintContainer);
     RenderLayer* renderLayer = repaintContainer->layer();
 
-    if (!renderLayer || renderLayer->compositingState() == NotComposited)
+    if (!renderLayer || !renderLayer->isComposited())
         return 0;
 
     GraphicsLayer* newGraphicsLayer = renderLayer->compositedLayerMapping()->mainGraphicsLayer();