Allow assertions to be enabled in Blink Release builds.

Source/core/rendering/compositing/CompositingRequirementsUpdater.cpp

 /*
  * Copyright (C) 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 121 matching lines @@
     }
 
     RenderLayer* m_compositingAncestor;
     bool m_subtreeIsCompositing;
     bool m_hasUnisolatedCompositedBlendingDescendant;
     bool m_testingOverlap;
 };
 
 static bool requiresCompositingOrSquashing(CompositingReasons reasons)
 {
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     bool fastAnswer = reasons != CompositingReasonNone;
     bool slowAnswer = requiresCompositing(reasons) || requiresSquashing(reasons);
     ASSERT(fastAnswer == slowAnswer);
 #endif
     return reasons != CompositingReasonNone;
 }
 
 static CompositingReasons subtreeReasonsForCompositing(RenderLayer* layer, bool hasCompositedDescendants, bool has3DTransformedDescendants)
 {
     CompositingReasons subtreeReasons = CompositingReasonNone;
@@ skipping 259 matching lines @@
 
         descendantHas3DTransform |= anyDescendantHas3DTransform || layer->has3DTransform();
     }
 
     // At this point we have finished collecting all reasons to composite this layer.
     layer->setCompositingReasons(reasonsToComposite);
 
 }
 
 } // namespace WebCore