Implement matching part of ::slotted() pseudo element

third_party/WebKit/Source/core/css/RuleFeature.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 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 134 matching lines @@
     case CSSSelector::PseudoWebKitCustomElement:
     case CSSSelector::PseudoCue:
     case CSSSelector::PseudoFutureCue:
     case CSSSelector::PseudoPastCue:
     case CSSSelector::PseudoUnresolved:
     case CSSSelector::PseudoContent:
     case CSSSelector::PseudoHost:
     case CSSSelector::PseudoShadow:
     case CSSSelector::PseudoSpatialNavigationFocus:
     case CSSSelector::PseudoListBox:
+    case CSSSelector::PseudoSlotted:
         return true;
     case CSSSelector::PseudoUnknown:
     case CSSSelector::PseudoLeftPage:
     case CSSSelector::PseudoRightPage:
     case CSSSelector::PseudoFirstPage:
         // These should not appear in StyleRule selectors.
         ASSERT_NOT_REACHED();
         return false;
     default:
         // New pseudo type added. Figure out if it needs a subtree invalidation or not.
         ASSERT_NOT_REACHED();
         return false;
     }
 }
 
 bool supportsInvalidationWithSelectorList(CSSSelector::PseudoType pseudo)
 {
     return pseudo == CSSSelector::PseudoAny
         || pseudo == CSSSelector::PseudoCue
         || pseudo == CSSSelector::PseudoHost
         || pseudo == CSSSelector::PseudoHostContext
-        || pseudo == CSSSelector::PseudoNot;
+        || pseudo == CSSSelector::PseudoNot
+        || pseudo == CSSSelector::PseudoSlotted;
 }
 
 #endif // ENABLE(ASSERT)
 
 bool requiresSubtreeInvalidation(const CSSSelector& selector)
 {
     if (selector.match() != CSSSelector::PseudoElement && selector.match() != CSSSelector::PseudoClass) {
         ASSERT(supportsInvalidation(selector.match()));
         return false;
     }
@@ skipping 321 matching lines @@
             if (const CSSSelectorList* selectorList = current->selectorList()) {
                 ASSERT(supportsInvalidationWithSelectorList(current->pseudoType()));
                 for (const CSSSelector* subSelector = selectorList->first(); subSelector; subSelector = CSSSelectorList::next(*subSelector))
                     addFeaturesToInvalidationSets(subSelector, siblingFeatures, descendantFeatures);
             }
         }
 
         if (current->relation() == CSSSelector::SubSelector)
             continue;
 
-        if (current->relationIsAffectedByPseudoContent()) {
+        if (current->relationIsAffectedByPseudoContent() || current->pseudoType() == CSSSelector::PseudoSlotted) {

[rune, 2016/01/20 12:53:32]

It would possibly be more consistent if you checked relation() for
CSSSelector::ShadowSlot instead, but it doesn't really matter as they'll always
occur in pairs?

[kochi, 2016/01/21 05:09:37]

Good suggestion.  Done.

             descendantFeatures.insertionPointCrossing = true;
             descendantFeatures.contentPseudoCrossing = true;
         }
         if (current->isShadowSelector())
             descendantFeatures.treeBoundaryCrossing = true;
         if (!current->isAdjacentSelector()) {
             lastCompoundSelectorInAdjacentChain = current->tagHistory();
             siblingFeatures = nullptr;
             continue;
         }
@@ skipping 191 matching lines @@
 
 DEFINE_TRACE(RuleFeatureSet)
 {
 #if ENABLE(OILPAN)
     visitor->trace(siblingRules);
     visitor->trace(uncommonAttributeRules);
 #endif
 }
 
 } // namespace blink