Invalidate CustomScrollbars on having window-inactive selector.

Source/core/css/RuleFeature.cpp

Index: Source/core/css/RuleFeature.cpp
diff --git a/Source/core/css/RuleFeature.cpp b/Source/core/css/RuleFeature.cpp
index 52e2eae7f086d1b556ac455572617c2e04aa94b0..ddb401d66e241015bab7c91e6cc0f973396da7e7 100644
--- a/Source/core/css/RuleFeature.cpp
+++ b/Source/core/css/RuleFeature.cpp
@@ -480,6 +480,8 @@ void RuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector, Ru
     for (const CSSSelector* current = &selector; current; current = current->tagHistory()) {
         if (current->pseudoType() == CSSSelector::PseudoFirstLine)
             metadata.usesFirstLineRules = true;
+        if (current->pseudoType() == CSSSelector::PseudoWindowInactive)
+            metadata.usesWindowInactiveSelector = true;
         if (current->isDirectAdjacentSelector()) {
             maxDirectAdjacentSelectors++;
         } else if (maxDirectAdjacentSelectors) {
@@ -504,12 +506,14 @@ void RuleFeatureSet::collectFeaturesFromSelector(const CSSSelector& selector, Ru
 void RuleFeatureSet::FeatureMetadata::add(const FeatureMetadata& other)
 {
     usesFirstLineRules = usesFirstLineRules || other.usesFirstLineRules;
+    usesWindowInactiveSelector = usesWindowInactiveSelector || other.usesWindowInactiveSelector;
     maxDirectAdjacentSelectors = std::max(maxDirectAdjacentSelectors, other.maxDirectAdjacentSelectors);
 }
 
 void RuleFeatureSet::FeatureMetadata::clear()
 {
     usesFirstLineRules = false;
+    usesWindowInactiveSelector = false;
     foundSiblingSelector = false;
     maxDirectAdjacentSelectors = 0;
 }