Allow assertions to be enabled in Blink Release builds.

Source/bindings/core/v8/V8PerIsolateData.h

 /*
  * Copyright (C) 2009 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 60 matching lines @@
 
     int recursionLevel() const { return m_recursionLevel; }
     int incrementRecursionLevel() { return ++m_recursionLevel; }
     int decrementRecursionLevel() { return --m_recursionLevel; }
     bool isHandlingRecursionLevelError() const { return m_isHandlingRecursionLevelError; }
     void setIsHandlingRecursionLevelError(bool value) { m_isHandlingRecursionLevelError = value; }
 
     bool performingMicrotaskCheckpoint() const { return m_performingMicrotaskCheckpoint; }
     void setPerformingMicrotaskCheckpoint(bool performingMicrotaskCheckpoint) { m_performingMicrotaskCheckpoint = performingMicrotaskCheckpoint; }
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     int internalScriptRecursionLevel() const { return m_internalScriptRecursionLevel; }
     int incrementInternalScriptRecursionLevel() { return ++m_internalScriptRecursionLevel; }
     int decrementInternalScriptRecursionLevel() { return --m_internalScriptRecursionLevel; }
 #endif
 
     GCEventData* gcEventData() { return m_gcEventData.get(); }
     V8HiddenValue* hiddenValue() { return m_hiddenValue.get(); }
 
     v8::Handle<v8::FunctionTemplate> domTemplate(void* domTemplateKey, v8::FunctionCallback = 0, v8::Handle<v8::Value> data = v8::Handle<v8::Value>(), v8::Handle<v8::Signature> = v8::Handle<v8::Signature>(), int length = 0);
     v8::Handle<v8::FunctionTemplate> existingDOMTemplate(void* domTemplateKey);
@@ skipping 27 matching lines @@
     RefPtr<ScriptState> m_scriptRegexpScriptState;
 
     const char* m_previousSamplingState;
 
     bool m_constructorMode;
     friend class ConstructorMode;
 
     int m_recursionLevel;
     bool m_isHandlingRecursionLevelError;
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     int m_internalScriptRecursionLevel;
 #endif
     OwnPtr<GCEventData> m_gcEventData;
     bool m_performingMicrotaskCheckpoint;
 };
 
 } // namespace WebCore
 
 #endif // V8PerIsolateData_h