Remove CSS regions support, keeping a bare minimum to support "region-based" multicol.

Source/core/css/StyleSheetContents.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple 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
  * 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 29 matching lines @@
 
 DEFINE_GC_INFO(StyleSheetContents);
 
 // Rough size estimate for the memory cache.
 unsigned StyleSheetContents::estimatedSizeInBytes() const
 {
     // Note that this does not take into account size of the strings hanging from various objects.
     // The assumption is that nearly all of of them are atomic and would exist anyway.
     unsigned size = sizeof(*this);
 
-    // FIXME: This ignores the children of media and region rules.
+    // FIXME: This ignores the children of media rules.
     // Most rules are StyleRules.
     size += ruleCount() * StyleRule::averageSizeInBytes();
 
     for (unsigned i = 0; i < m_importRules.size(); ++i) {
         if (StyleSheetContents* sheet = m_importRules[i]->styleSheet())
             size += sheet->estimatedSizeInBytes();
     }
     return size;
 }
 
@@ skipping 413 matching lines @@
                 return true;
             break;
         case StyleRuleBase::FontFace:
             if (toStyleRuleFontFace(rule)->properties()->hasFailedOrCanceledSubresources())
                 return true;
             break;
         case StyleRuleBase::Media:
             if (childRulesHaveFailedOrCanceledSubresources(toStyleRuleMedia(rule)->childRules()))
                 return true;
             break;
-        case StyleRuleBase::Region:
-            if (childRulesHaveFailedOrCanceledSubresources(toStyleRuleRegion(rule)->childRules()))
-                return true;
-            break;
         case StyleRuleBase::Import:
             ASSERT_NOT_REACHED();
         case StyleRuleBase::Page:
         case StyleRuleBase::Keyframes:
         case StyleRuleBase::Unknown:
         case StyleRuleBase::Charset:
         case StyleRuleBase::Keyframe:
         case StyleRuleBase::Supports:
         case StyleRuleBase::Viewport:
         case StyleRuleBase::Filter:
@@ skipping 75 matching lines @@
     }
     m_ruleSet.clear();
 }
 
 
 void StyleSheetContents::trace(Visitor*)
 {
 }
 
 }