Removed TODO as non-matching host rules are skipped earlier.

third_party/WebKit/Source/core/css/RuleSet.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 186 matching lines @@
         return true;
     default:
         break;
     }
 
     if (!tagName.isEmpty()) {
         addToRuleSet(tagName, ensurePendingRules()->tagRules, ruleData);
         return true;
     }
 
-    // TODO(esprehn): We shouldn't favor tagName over m_shadowHostRules, it means
-    // selectors with div:host end up in the tagName list matched against all tags
-    // even though they can't match anything at all.
     if (component.isHostPseudoClass()) {
+        ASSERT(component.isLastInTagHistory() || (component.relation() == CSSSelector::SubSelector && component.tagHistory()->match() == CSSSelector::PseudoElement));
         m_shadowHostRules.append(ruleData);
         return true;
     }
 
     return false;
 }
 
 void RuleSet::addRule(StyleRule* rule, unsigned selectorIndex, AddRuleFlags addRuleFlags)
 {
     RuleData ruleData(rule, selectorIndex, m_ruleCount++, addRuleFlags);
@@ skipping 180 matching lines @@
 
 #ifndef NDEBUG
 void RuleSet::show() const
 {
     for (const auto& rule: m_allRules)
         rule.selector().show();
 }
 #endif
 
 } // namespace blink