Consider pseudo classes as matching for shared style rejection.

third_party/WebKit/Source/core/css/CSSSelector.h

Index: third_party/WebKit/Source/core/css/CSSSelector.h
diff --git a/third_party/WebKit/Source/core/css/CSSSelector.h b/third_party/WebKit/Source/core/css/CSSSelector.h
index 766005b1d82533949068e5014dfce4c3c20a4c9a..c7dd1b97ea55890b778acbe1676c2c68c1120d79 100644
--- a/third_party/WebKit/Source/core/css/CSSSelector.h
+++ b/third_party/WebKit/Source/core/css/CSSSelector.h
@@ -260,6 +260,7 @@ public:
     bool isShadowSelector() const { return m_relation == ShadowPseudo || m_relation == ShadowDeep; }
     bool isAttributeSelector() const { return m_match >= FirstAttributeSelectorMatch; }
     bool isHostPseudoClass() const { return m_pseudoType == PseudoHost || m_pseudoType == PseudoHostContext; }
+    bool isUserActionPseudoClass() const;
     bool isInsertionPointCrossing() const { return m_pseudoType == PseudoHostContext || m_pseudoType == PseudoContent; }
 
     RelationType relation() const { return static_cast<RelationType>(m_relation); }
@@ -483,6 +484,14 @@ inline const AtomicString& CSSSelector::serializingValue() const
     return *reinterpret_cast<const AtomicString*>(&m_data.m_value);
 }
 
+inline bool CSSSelector::isUserActionPseudoClass() const
+{
+    return m_pseudoType == PseudoHover
+        || m_pseudoType == PseudoActive
+        || m_pseudoType == PseudoFocus
+        || m_pseudoType == PseudoDrag;
+}
+
 } // namespace blink
 
 #endif // CSSSelector_h