Have ElementRuleCollector keep match result vector as part object.

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 63 matching lines @@
 }
 
 PassRefPtrWillBeRawPtr<CSSRuleList> ElementRuleCollector::matchedCSSRuleList()
 {
     ASSERT(m_mode == SelectorChecker::CollectingCSSRules);
     return m_cssRuleList.release();
 }
 
 inline void ElementRuleCollector::addMatchedRule(const RuleData* rule, unsigned specificity, CascadeScope cascadeScope, CascadeOrder cascadeOrder, unsigned styleSheetIndex, const CSSStyleSheet* parentStyleSheet)
 {
-    if (!m_matchedRules)
-        m_matchedRules = adoptPtrWillBeNoop(new WillBeHeapVector<MatchedRule, 32>);
-    m_matchedRules->append(MatchedRule(rule, specificity, cascadeScope, cascadeOrder, styleSheetIndex, parentStyleSheet));
+    m_matchedRules.append(MatchedRule(rule, specificity, cascadeScope, cascadeOrder, styleSheetIndex, parentStyleSheet));
 }
 
 void ElementRuleCollector::clearMatchedRules()
 {
-    if (!m_matchedRules)
-        return;
-    m_matchedRules->clear();
+    m_matchedRules.clear();
 }
 
 inline StyleRuleList* ElementRuleCollector::ensureStyleRuleList()
 {
     if (!m_styleRuleList)
         m_styleRuleList = StyleRuleList::create();
     return m_styleRuleList.get();
 }
 
 inline StaticCSSRuleList* ElementRuleCollector::ensureRuleList()
@@ skipping 116 matching lines @@
     if (parentStyleSheet)
         cssRule = findStyleRule(parentStyleSheet, rule);
     else
         cssRule = rule->createCSSOMWrapper();
     ASSERT(!parentStyleSheet || cssRule);
     ensureRuleList()->rules().append(cssRule);
 }
 
 void ElementRuleCollector::sortAndTransferMatchedRules()
 {
-    if (!m_matchedRules || m_matchedRules->isEmpty())
+    if (m_matchedRules.isEmpty())
         return;
 
     sortMatchedRules();
 
-    WillBeHeapVector<MatchedRule, 32>& matchedRules = *m_matchedRules;
+    WillBeHeapVector<MatchedRule, 32>& matchedRules = m_matchedRules;

[rune, 2014/12/12 07:10:35]

Is it really necessary to have a new reference here? Couldn't m_matchedRules be
used directly below?

[sof, 2014/12/12 07:13:23]

Yes, we can simplify this away now. Will do.

     if (m_mode == SelectorChecker::CollectingStyleRules) {
         for (unsigned i = 0; i < matchedRules.size(); ++i)
             ensureStyleRuleList()->m_list.append(matchedRules[i].ruleData()->rule());
         return;
     }
 
     if (m_mode == SelectorChecker::CollectingCSSRules) {
         for (unsigned i = 0; i < matchedRules.size(); ++i)
             appendCSSOMWrapperForRule(const_cast<CSSStyleSheet*>(matchedRules[i].parentStyleSheet()), matchedRules[i].ruleData()->rule());
         return;
@@ skipping 77 matching lines @@
     unsigned specificity1 = matchedRule1.specificity();
     unsigned specificity2 = matchedRule2.specificity();
     if (specificity1 != specificity2)
         return specificity1 < specificity2;
 
     return matchedRule1.position() < matchedRule2.position();
 }
 
 void ElementRuleCollector::sortMatchedRules()
 {
-    ASSERT(m_matchedRules);
-    std::sort(m_matchedRules->begin(), m_matchedRules->end(), compareRules);
+    std::sort(m_matchedRules.begin(), m_matchedRules.end(), compareRules);
 }
 
 bool ElementRuleCollector::hasAnyMatchingRules(RuleSet* ruleSet)
 {
     clearMatchedRules();
 
     m_mode = SelectorChecker::SharingRules;
     // To check whether a given RuleSet has any rule matching a given element,
     // should not see the element's treescope. Because RuleSet has no
     // 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);
 
-    return m_matchedRules && !m_matchedRules->isEmpty();
+    return !m_matchedRules.isEmpty();
 }
 
 } // namespace blink