*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/css/ElementRuleCollector.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 24 matching lines @@
 #include "core/css/CSSRuleList.h"
 #include "core/css/CSSSelector.h"
 #include "core/css/CSSStyleRule.h"
 #include "core/css/CSSStyleSheet.h"
 #include "core/css/CSSSupportsRule.h"
 #include "core/css/SelectorCheckerFastPath.h"
 #include "core/css/SiblingTraversalStrategies.h"
 #include "core/css/StylePropertySet.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/dom/shadow/ShadowRoot.h"
-#include "core/rendering/RenderRegion.h"
 
 namespace WebCore {
 
 ElementRuleCollector::ElementRuleCollector(const ElementResolveContext& context,
     const SelectorFilter& filter, RenderStyle* style)
     : m_context(context)
     , m_selectorFilter(filter)
     , m_style(style)
-    , m_regionForStyling(0)
     , m_pseudoStyleRequest(NOPSEUDO)
     , m_mode(SelectorChecker::ResolvingStyle)
     , m_canUseFastReject(m_selectorFilter.parentStackIsConsistent(context.parentNode()))
     , m_sameOriginOnly(false)
     , m_matchingUARules(false)
 { }
 
 ElementRuleCollector::~ElementRuleCollector()
 {
 }
@@ skipping 106 matching lines @@
     }
 
     if (element.isLink())
         collectMatchingRulesForList(matchRequest.ruleSet->linkPseudoClassRules(), behaviorAtBoundary, cascadeScope, cascadeOrder, matchRequest, ruleRange);
     if (SelectorChecker::matchesFocusPseudoClass(element))
         collectMatchingRulesForList(matchRequest.ruleSet->focusPseudoClassRules(), behaviorAtBoundary, cascadeScope, cascadeOrder, matchRequest, ruleRange);
     collectMatchingRulesForList(matchRequest.ruleSet->tagRules(element.localName().impl()), behaviorAtBoundary, cascadeScope, cascadeOrder, matchRequest, ruleRange);
     collectMatchingRulesForList(matchRequest.ruleSet->universalRules(), behaviorAtBoundary, cascadeScope, cascadeOrder, matchRequest, ruleRange);
 }
 
-void ElementRuleCollector::collectMatchingRulesForRegion(const MatchRequest& matchRequest, RuleRange& ruleRange, SelectorChecker::BehaviorAtBoundary behaviorAtBoundary, CascadeScope cascadeScope, CascadeOrder cascadeOrder)
-{
-    if (!m_regionForStyling)
-        return;
-
-    unsigned size = matchRequest.ruleSet->m_regionSelectorsAndRuleSets.size();
-    for (unsigned i = 0; i < size; ++i) {
-        const CSSSelector* regionSelector = matchRequest.ruleSet->m_regionSelectorsAndRuleSets.at(i).selector;
-        if (checkRegionSelector(regionSelector, toElement(m_regionForStyling->nodeForRegion()))) {
-            RuleSet* regionRules = matchRequest.ruleSet->m_regionSelectorsAndRuleSets.at(i).ruleSet.get();
-            ASSERT(regionRules);
-            collectMatchingRules(MatchRequest(regionRules, matchRequest.includeEmptyRules, matchRequest.scope), ruleRange, behaviorAtBoundary, cascadeScope, cascadeOrder);
-        }
-    }
-}
 
 CSSRuleList* ElementRuleCollector::nestedRuleList(CSSRule* rule)
 {
     switch (rule->type()) {
     case CSSRule::MEDIA_RULE:
         return toCSSMediaRule(rule)->cssRules();
     case CSSRule::KEYFRAMES_RULE:
         return toCSSKeyframesRule(rule)->cssRules();
     case CSSRule::SUPPORTS_RULE:
         return toCSSSupportsRule(rule)->cssRules();
@@ skipping 194 matching lines @@
     // information about "scope".
     int firstRuleIndex = -1, lastRuleIndex = -1;
     RuleRange ruleRange(firstRuleIndex, lastRuleIndex);
     // FIXME: Verify whether it's ok to ignore CascadeScope here.
     collectMatchingRules(MatchRequest(ruleSet), ruleRange, SelectorChecker::StaysWithinTreeScope);
 
     return m_matchedRules && !m_matchedRules->isEmpty();
 }
 
 } // namespace WebCore