CSS: Avoid invalidating style when only descendants need updating

Source/core/css/invalidation/InvalidationSet.cpp

Index: Source/core/css/invalidation/InvalidationSet.cpp
diff --git a/Source/core/css/invalidation/InvalidationSet.cpp b/Source/core/css/invalidation/InvalidationSet.cpp
index 617e9b974e5a946d7dfabd2307c2c5c4e39b0b1e..24b70d7d0a4e8ca7b749ef8f6e578ecb2461fce9 100644
--- a/Source/core/css/invalidation/InvalidationSet.cpp
+++ b/Source/core/css/invalidation/InvalidationSet.cpp
@@ -53,6 +53,7 @@ void InvalidationSet::cacheTracingFlag()
 
 InvalidationSet::InvalidationSet()
     : m_allDescendantsMightBeInvalid(false)
+    , m_invalidatesSelf(false)
     , m_customPseudoInvalid(false)
     , m_treeBoundaryCrossing(false)
     , m_insertionPointCrossing(false)
@@ -107,6 +108,9 @@ void InvalidationSet::combine(const InvalidationSet& other)
         return;
     }
 
+    if (other.invalidatesSelf())
+        setInvalidatesSelf();
+
     if (other.customPseudoInvalid())
         setCustomPseudoInvalid();