[CSS Regions] Elements in a region should be assignable to a named flow

Source/core/rendering/FlowThreadController.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 208 matching lines @@
         flowRenderer->layoutIfNeeded();
         if (flowRenderer->hasAutoLogicalHeightRegions()) {
             ASSERT(flowRenderer->needsTwoPhasesLayout());
             flowRenderer->markAutoLogicalHeightRegionsForLayout();
         }
         flowRenderer->setInConstrainedLayoutPhase(true);
         flowRenderer->clearNeedsTwoPhasesLayout();
     }
 }
 
+bool FlowThreadController::isContentNodeRegisteredWithAnyNamedFlow(Node* contentNode) const
+{
+    return m_mapNamedFlowContentNodes.contains(contentNode);
+}
+
 #ifndef NDEBUG
 bool FlowThreadController::isAutoLogicalHeightRegionsCountConsistent() const
 {
     if (!hasRenderNamedFlowThreads())
         return !hasFlowThreadsWithAutoLogicalHeightRegions();
 
     for (RenderNamedFlowThreadList::iterator iter = m_renderNamedFlowThreadList->begin(); iter != m_renderNamedFlowThreadList->end(); ++iter) {
         if (!(*iter)->isAutoLogicalHeightRegionsCountConsistent())
             return false;
     }
 
     return true;
 }
 #endif
 
 } // namespace WebCore