Handle ::content and :host-context correctly in SelectorQuery.

Source/core/dom/SelectorQuery.cpp

 /*
  * Copyright (C) 2011, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2014 Samsung Electronics. 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 89 matching lines @@
 
 void SelectorDataList::initialize(const CSSSelectorList& selectorList)
 {
     ASSERT(m_selectors.isEmpty());
 
     unsigned selectorCount = 0;
     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector))
         selectorCount++;
 
     m_crossesTreeBoundary = false;
+    m_needsUpdatedDistribution = false;
     m_selectors.reserveInitialCapacity(selectorCount);
     unsigned index = 0;
     for (const CSSSelector* selector = selectorList.first(); selector; selector = CSSSelectorList::next(*selector), ++index) {
         m_selectors.uncheckedAppend(selector);
         m_crossesTreeBoundary |= selectorList.selectorCrossesTreeScopes(index);
+        m_needsUpdatedDistribution |= selectorList.selectorNeedsUpdatedDistribution(index);
     }
 }
 
 inline bool SelectorDataList::selectorMatches(const CSSSelector& selector, Element& element, const ContainerNode& rootNode) const
 {
     SelectorChecker selectorChecker(SelectorChecker::QueryingRules);
     SelectorChecker::SelectorCheckingContext selectorCheckingContext(&element, SelectorChecker::VisitedMatchDisabled);
     selectorCheckingContext.selector = &selector;
     selectorCheckingContext.scope = !rootNode.isDocumentNode() ? &rootNode : 0;
     if (selectorCheckingContext.scope)
         selectorCheckingContext.scopeContainsLastMatchedElement = true;
     return selectorChecker.match(selectorCheckingContext);
 }
 
 bool SelectorDataList::matches(Element& targetElement) const
 {
+    if (m_needsUpdatedDistribution)
+        targetElement.updateDistribution();
+
     unsigned selectorCount = m_selectors.size();
     for (unsigned i = 0; i < selectorCount; ++i) {
         if (selectorMatches(*m_selectors[i], targetElement, targetElement))
             return true;
     }
 
     return false;
 }
 
 Element* SelectorDataList::closest(Element& targetElement) const
 {
+    if (m_needsUpdatedDistribution)
+        targetElement.updateDistribution();
+
     unsigned selectorCount = m_selectors.size();
     for (Element* currentElement = &targetElement; currentElement; currentElement = currentElement->parentElement()) {
         for (unsigned i = 0; i < selectorCount; ++i) {
             if (selectorMatches(*m_selectors[i], *currentElement, targetElement))
                 return currentElement;
         }
     }
     return nullptr;
 }
 
@@ skipping 48 matching lines @@
         if (matchesTagName(tagName, element)) {
             SelectorQueryTrait::appendElement(output, element);
             if (SelectorQueryTrait::shouldOnlyMatchFirstElement)
                 return;
         }
     }
 }
 
 inline bool SelectorDataList::canUseFastQuery(const ContainerNode& rootNode) const
 {
-    return m_selectors.size() == 1 && !m_crossesTreeBoundary && rootNode.inDocument() && !rootNode.document().inQuirksMode();
+    if (m_crossesTreeBoundary)
+        return false;
+    if (m_needsUpdatedDistribution)
+        return false;
+    if (rootNode.document().inQuirksMode())
+        return false;
+    if (!rootNode.inDocument())
+        return false;
+    return m_selectors.size() == 1;
 }
 
 inline bool ancestorHasClassName(ContainerNode& rootNode, const AtomicString& className)
 {
     if (!rootNode.isElementNode())
         return false;
 
     for (Element* element = &toElement(rootNode); element; element = element->parentElement()) {
         if (element->hasClass() && element->classNames().contains(className))
             return true;
@@ skipping 211 matching lines @@
         if (selector->relation() != CSSSelector::SubSelector)
             break;
     }
     return 0;
 }
 
 template <typename SelectorQueryTrait>
 void SelectorDataList::execute(ContainerNode& rootNode, typename SelectorQueryTrait::OutputType& output) const
 {
     if (!canUseFastQuery(rootNode)) {
+        if (m_needsUpdatedDistribution)
+            rootNode.updateDistribution();
         if (m_crossesTreeBoundary) {
-            rootNode.updateDistribution();
             executeSlowTraversingShadowTree<SelectorQueryTrait>(rootNode, output);
         } else {
             executeSlow<SelectorQueryTrait>(rootNode, output);
         }
         return;
     }
 
     ASSERT(m_selectors.size() == 1);
 
     const CSSSelector& selector = *m_selectors[0];
@@ skipping 99 matching lines @@
 
     return m_entries.add(selectors, SelectorQuery::adopt(selectorList)).storedValue->value.get();
 }
 
 void SelectorQueryCache::invalidate()
 {
     m_entries.clear();
 }
 
 }