Styling slot fallback content with ::slotted()

third_party/WebKit/Source/core/css/resolver/ScopedStyleResolver.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
  * All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
@@ skipping 258 matching lines @@
     const MinimalRuleData& info = rules[i];
     rule_set->AddRule(info.rule_, info.selector_index_, info.flags_);
   }
 }
 
 void ScopedStyleResolver::AddTreeBoundaryCrossingRules(
     const RuleSet& author_rules,
     CSSStyleSheet* parent_style_sheet,
     unsigned sheet_index) {
   bool is_document_scope = GetTreeScope().RootNode().IsDocumentNode();
+
+  // ::slotted() rules have to be allowed for Document for styling fallback
+  // contents in <slot>.
   if (author_rules.DeepCombinatorOrShadowPseudoRules().IsEmpty() &&
+      author_rules.SlottedPseudoElementRules().IsEmpty() &&
       (is_document_scope ||
-       (author_rules.ContentPseudoElementRules().IsEmpty() &&
-        author_rules.SlottedPseudoElementRules().IsEmpty())))
+       (author_rules.ContentPseudoElementRules().IsEmpty())))
     return;
 
   if (!author_rules.DeepCombinatorOrShadowPseudoRules().IsEmpty())
     has_deep_or_shadow_selector_ = true;
 
   RuleSet* rule_set_for_scope = RuleSet::Create();
   AddRules(rule_set_for_scope,
            author_rules.DeepCombinatorOrShadowPseudoRules());
+  AddRules(rule_set_for_scope, author_rules.SlottedPseudoElementRules());
 
-  if (!is_document_scope) {
+  if (!is_document_scope)
     AddRules(rule_set_for_scope, author_rules.ContentPseudoElementRules());
-    AddRules(rule_set_for_scope, author_rules.SlottedPseudoElementRules());
-  }
 
   if (!tree_boundary_crossing_rule_set_) {
     tree_boundary_crossing_rule_set_ = new CSSStyleSheetRuleSubSet();
     GetTreeScope().GetDocument().GetStyleEngine().AddTreeBoundaryCrossingScope(
         GetTreeScope());
   }
 
   tree_boundary_crossing_rule_set_->push_back(
       RuleSubSet::Create(parent_style_sheet, sheet_index, rule_set_for_scope));
 }
@@ skipping 19 matching lines @@
   }
   return true;
 }
 
 DEFINE_TRACE(ScopedStyleResolver::RuleSubSet) {
   visitor->Trace(parent_style_sheet_);
   visitor->Trace(rule_set_);
 }
 
 }  // namespace blink