Remove CSS_REGIONS compile flag from Blink.

Source/core/dom/NodeRenderingContext.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 167 matching lines @@
         return false;
     if (!m_renderingParent->childShouldCreateRenderer(*this))
         return false;
     return true;
 }
 
 void NodeRenderingContext::moveToFlowThreadIfNeeded()
 {
     ASSERT(m_node->isElementNode());
     ASSERT(m_style);
-    if (!m_node->document()->cssRegionsEnabled())
+    if (!RuntimeEnabledFeatures::cssRegionsEnabled())
         return;
 
     if (m_style->flowThread().isEmpty())
         return;
 
     // As per http://dev.w3.org/csswg/css3-regions/#flow-into, pseudo-elements such as ::first-line, ::first-letter, ::before or ::after
     // cannot be directly collected into a named flow.
     if (m_node->isPseudoElement())
         return;
 
@@ skipping 107 matching lines @@
     newRenderer->setFlowThreadState(parentRenderer->flowThreadState());
 
     RenderObject* nextRenderer = this->nextRenderer();
     textNode->setRenderer(newRenderer);
     // Parent takes care of the animations, no need to call setAnimatableStyle.
     newRenderer->setStyle(m_style.release());
     parentRenderer->addChild(newRenderer, nextRenderer);
 }
 
 }