Allow assertions to be enabled in Blink Release builds.

Source/core/dom/NoEventDispatchAssertion.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NoEventDispatchAssertion_h
 #define NoEventDispatchAssertion_h
 
 #include "wtf/MainThread.h"
 #include "wtf/TemporaryChange.h"
 
 namespace WebCore {
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
 
 class NoEventDispatchAssertion {
 public:
     NoEventDispatchAssertion()
     {
         if (!isMainThread())
             return;
         ++s_count;
     }
 
@@ skipping 38 matching lines @@
 class NoEventDispatchAssertion {
 public:
     NoEventDispatchAssertion() { }
 
     class AllowSVGImageEvents {
     public:
         AllowSVGImageEvents() { }
     };
 };
 
-#endif // NDEBUG
+#endif // ENABLE(ASSERT)
 
 } // namespace WebCore
 
 #endif // NoEventDispatchAssertion_h