Allow assertions to be enabled in Blink Release builds.

Source/core/page/Page.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 119 matching lines @@
     , m_spellCheckerClient(pageClients.spellCheckerClient)
     , m_storageClient(pageClients.storageClient)
     , m_subframeCount(0)
     , m_openedByDOM(false)
     , m_tabKeyCyclesThroughElements(true)
     , m_defersLoading(false)
     , m_deviceScaleFactor(1)
     , m_timerAlignmentInterval(DOMTimer::visiblePageAlignmentInterval())
     , m_visibilityState(PageVisibilityStateVisible)
     , m_isCursorVisible(true)
-#ifndef NDEBUG
+#if ENABLE(ASSERT)
     , m_isPainting(false)
 #endif
     , m_frameHost(FrameHost::create(*this))
 {
     ASSERT(m_editorClient);
 
     ASSERT(!allPages().contains(this));
     allPages().add(this);
 
 #ifndef NDEBUG
@@ skipping 505 matching lines @@
     , spellCheckerClient(0)
     , storageClient(0)
 {
 }
 
 Page::PageClients::~PageClients()
 {
 }
 
 } // namespace WebCore