Remove CSS_REGIONS compile flag from Blink.

Source/core/dom/NamedFlowCollection.cpp

 /*
  * Copyright (C) 2012 Adobe Systems Incorporated. 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.
@@ skipping 12 matching lines @@
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 
 #include "config.h"
 #include "core/dom/NamedFlowCollection.h"
 
+#include "RuntimeEnabledFeatures.h"
 #include "core/dom/DOMNamedFlowCollection.h"
 #include "core/dom/Document.h"
 #include "core/dom/NamedFlow.h"
 #include "core/inspector/InspectorInstrumentation.h"
 
 #include <wtf/text/StringHash.h>
 #include <wtf/text/WTFString.h>
 
 namespace WebCore {
 
 NamedFlowCollection::NamedFlowCollection(Document* document)
     : ContextDestructionObserver(document)
 {
+    ASSERT(RuntimeEnabledFeatures::cssRegionsEnabled());
 }
 
 Vector<RefPtr<NamedFlow> > NamedFlowCollection::namedFlows()
 {
     Vector<RefPtr<NamedFlow> > namedFlows;
 
     for (NamedFlowSet::iterator it = m_namedFlows.begin(); it != m_namedFlows.end(); ++it) {
         if ((*it)->flowState() == NamedFlow::FlowStateNull)
             continue;
 
@@ skipping 67 matching lines @@
     static const bool safeToCompareToEmptyOrDeleted = true;
 };
 
 // The HashTranslator is used to lookup a NamedFlow in the set using a name.
 struct NamedFlowCollection::NamedFlowHashTranslator {
     static unsigned hash(const String& key) { return DefaultHash<String>::Hash::hash(key); }
     static bool equal(NamedFlow* a, const String& b) { return a->name() == b; }
 };
 
 } // namespace WebCore