Fix assignedNodes({flatten:true}) to return fallback content in document tree

third_party/WebKit/Source/core/dom/StyleEngine.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 853 matching lines @@
     const HeapHashSet<Member<RuleSet>>& rule_sets) {
   InvalidationLists invalidation_lists;
   for (const auto& rule_set : rule_sets)
     rule_set->Features().CollectTypeRuleInvalidationSet(invalidation_lists,
                                                         node);
   DCHECK(invalidation_lists.siblings.IsEmpty());
   style_invalidator_.ScheduleInvalidationSetsForNode(invalidation_lists, node);
 }
 
 void StyleEngine::InvalidateSlottedElements(HTMLSlotElement& slot) {
-  for (auto& node : slot.GetDistributedNodes()) {
+  for (auto& node : slot.GetDistributedNodesExcludingFallback()) {

[hayato, 2017/05/18 06:58:25]

Is this correct? Why doesn't this need to invalidate fallback elements?

[kochi, 2017/05/18 07:21:49]

If this is not correct, I'll file another bug.
This should not change from the previous behavior, because the old
GetDistributedNodes() returned its internal distributed_nodes_
which doesn't include fallback content.

     if (node->IsElementNode())
       node->SetNeedsStyleRecalc(kLocalStyleChange,
                                 StyleChangeReasonForTracing::Create(
                                     StyleChangeReason::kStyleSheetChange));
   }
 }
 
 void StyleEngine::ScheduleInvalidationsForRuleSets(
     TreeScope& tree_scope,
     const HeapHashSet<Member<RuleSet>>& rule_sets) {
@@ skipping 20 matching lines @@
         invalidate_slotted = true;
         break;
       }
     }
   }
 
   Node* stay_within = &tree_scope.RootNode();
   Element* element = ElementTraversal::FirstChild(*stay_within);
   while (element) {
     ScheduleRuleSetInvalidationsForElement(*element, rule_sets);
-    if (invalidate_slotted && isHTMLSlotElement(element))
+    if (invalidate_slotted && isHTMLSlotElement(element) &&
+        toHTMLSlotElement(element)->SupportsDistribution())
       InvalidateSlottedElements(toHTMLSlotElement(*element));
 
     if (element->GetStyleChangeType() < kSubtreeStyleChange)
       element = ElementTraversal::Next(*element, stay_within);
     else
       element = ElementTraversal::NextSkippingChildren(*element, stay_within);
   }
 }
 
 void StyleEngine::SetStatsEnabled(bool enabled) {
@@ skipping 275 matching lines @@
 }
 
 DEFINE_TRACE_WRAPPERS(StyleEngine) {
   for (auto sheet : injected_author_style_sheets_) {
     visitor->TraceWrappers(sheet);
   }
   visitor->TraceWrappers(document_style_sheet_collection_);
 }
 
 }  // namespace blink