| Index: third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp | 
| diff --git a/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp b/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp | 
| index 33cf98c2e322e903649f84df59445c8d4395f732..c40cc084a4fa8ada133566946e354430a3f1285f 100644 | 
| --- a/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp | 
| +++ b/third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp | 
| @@ -164,6 +164,9 @@ void ScopedStyleResolver::collectMatchingShadowHostRules(ElementRuleCollector& c | 
|  | 
| void ScopedStyleResolver::collectMatchingTreeBoundaryCrossingRules(ElementRuleCollector& collector, CascadeOrder cascadeOrder) | 
| { | 
| +    if (!m_treeBoundaryCrossingRuleSet) | 
| +        return; | 
| + | 
| for (const auto& rules : *m_treeBoundaryCrossingRuleSet) { | 
| MatchRequest request(rules->m_ruleSet.get(), &treeScope().rootNode(), rules->m_parentStyleSheet, rules->m_parentIndex); | 
| collector.collectMatchingRules(request, cascadeOrder, true); | 
|  |