Introduce ASSERT_ENABLED macro.

Source/wtf/ThreadRestrictionVerifier.h

 /*
  * Copyright (C) 2011 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 35 matching lines @@
 public:
     ThreadRestrictionVerifier()
         : m_shared(false)
         , m_owningThread(0)
     {
     }
 
     // Indicates that the object may (or may not) be owned by more than one place.
     void setShared(bool shared)
     {
-#if !ASSERT_DISABLED
+#if ASSERT_ENABLED
         bool previouslyShared = m_shared;
 #endif
         m_shared = shared;
 
         if (!m_shared)
             return;
 
         ASSERT(shared != previouslyShared);
         // Capture the current thread to verify that subsequent ref/deref happen on this thread.
         m_owningThread = currentThread();
@@ skipping 12 matching lines @@
     bool m_shared;
 
     // Used by SingleThreadVerificationMode
     ThreadIdentifier m_owningThread;
 };
 
 }
 
 #endif // !NDEBUG
 #endif // ThreadRestrictionVerifier_h