Allow multiple host pseudos in same compound.

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 592 matching lines @@
         case CSSSelector::PseudoOnlyOfType:
         case CSSSelector::PseudoNthChild:
         case CSSSelector::PseudoNthOfType:
         case CSSSelector::PseudoNthLastChild:
         case CSSSelector::PseudoNthLastOfType:
             if (!metadata.foundInsertionPointCrossing)
                 metadata.foundSiblingSelector = true;
             break;
         case CSSSelector::PseudoHost:
         case CSSSelector::PseudoHostContext:
-            if (relation == CSSSelector::SubSelector)
+            if (!foundHostPseudo && relation == CSSSelector::SubSelector)
                 return SelectorNeverMatches;
-            if (!current->isLastInTagHistory() && current->tagHistory()->match() != CSSSelector::PseudoElement)
+            if (!current->isLastInTagHistory()
+                && current->tagHistory()->match() != CSSSelector::PseudoElement
+                && !current->tagHistory()->isHostPseudoClass()) {
                 return SelectorNeverMatches;
+            }
             foundHostPseudo = true;
             // fall through.
         default:
             if (const CSSSelectorList* selectorList = current->selectorList()) {
                 for (const CSSSelector* subSelector = selectorList->first(); subSelector; subSelector = CSSSelectorList::next(*subSelector))
                     collectFeaturesFromSelector(*subSelector, metadata);
             }
             break;
         }
 
@@ skipping 150 matching lines @@
     }
 }
 
 DEFINE_TRACE(RuleFeatureSet)
 {
     visitor->trace(siblingRules);
     visitor->trace(uncommonAttributeRules);
 }
 
 } // namespace blink