Allow assertions to be enabled in Blink Release builds.

Source/core/page/Page.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 185 matching lines @@
     // recursive frameset pages can quickly bring the program to its knees
     // with exponential growth in the number of frames.
     static const int maxNumberOfFrames = 1000;
 
     PageVisibilityState visibilityState() const;
     void setVisibilityState(PageVisibilityState, bool);
 
     bool isCursorVisible() const;
     void setIsCursorVisible(bool isVisible) { m_isCursorVisible = isVisible; }
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     void setIsPainting(bool painting) { m_isPainting = painting; }
     bool isPainting() const { return m_isPainting; }
 #endif
 
     double timerAlignmentInterval() const;
 
     class MultisamplingChangedObserver : public WillBeGarbageCollectedMixin {
     public:
         virtual void multisamplingChanged(bool) = 0;
     };
@@ skipping 75 matching lines @@
     float m_deviceScaleFactor;
 
     OwnPtr<StorageNamespace> m_sessionStorage;
 
     double m_timerAlignmentInterval;
 
     PageVisibilityState m_visibilityState;
 
     bool m_isCursorVisible;
 
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     bool m_isPainting;
 #endif
 
     WillBeHeapHashSet<RawPtrWillBeWeakMember<MultisamplingChangedObserver> > m_multisamplingChangedObservers;
 
     // A pointer to all the interfaces provided to in-process Frames for this Page.
     // FIXME: Most of the members of Page should move onto FrameHost.
     OwnPtrWillBeMember<FrameHost> m_frameHost;
 };
 
 } // namespace WebCore
 
 #endif // Page_h