Stop re-signaling a slotchange event

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  *
@@ skipping 2326 matching lines @@
 
   DCHECK(isHTMLElement() || isSVGElement());
   DCHECK(CustomElementState::Custom != getCustomElementState());
   setFlag(V0CustomElementFlag);
   setFlag(newState == V0Upgraded, V0CustomElementUpgradedFlag);
 
   if (oldState == V0NotCustomElement || newState == V0Upgraded)
     toElement(this)->pseudoStateChanged(CSSSelector::PseudoUnresolved);
 }
 
-void Node::checkSlotChange() {
+void Node::checkSlotChange(SlotChangeType slotChangeType) {
   // Common check logic is used in both cases, "after inserted" and "before
   // removed".
   if (!isSlotable())
     return;
   if (ShadowRoot* root = v1ShadowRootOfParent()) {
     // Relevant DOM Standard:
     // https://dom.spec.whatwg.org/#concept-node-insert
     // - 6.1.2: If parent is a shadow host and node is a slotable, then assign a
     //   slot for node.
     // https://dom.spec.whatwg.org/#concept-node-remove
     // - 10. If node is assigned, then run assign slotables for node’s assigned
     //   slot.
 
     // Although DOM Standard requires "assign a slot for node / run assign
     // slotables" at this timing, we skip it as an optimization.
     if (HTMLSlotElement* slot = root->ensureSlotAssignment().findSlot(*this))
-      slot->enqueueSlotChangeEvent();
+      slot->didSlotChange(slotChangeType);
   } else {
     // Relevant DOM Standard:
     // https://dom.spec.whatwg.org/#concept-node-insert
     // - 6.1.3: If parent is a slot whose assigned nodes is the empty list, then
     //   run signal a slot change for parent.
     // https://dom.spec.whatwg.org/#concept-node-remove
     // - 11. If parent is a slot whose assigned nodes is the empty list, then
     //   run signal a slot change for parent.
     Element* parent = parentElement();
     if (parent && isHTMLSlotElement(parent)) {
       HTMLSlotElement& parentSlot = toHTMLSlotElement(*parent);
       if (ShadowRoot* root = containingShadowRoot()) {
         if (root && root->isV1() && !parentSlot.hasAssignedNodesSlow())

[kochi, 2016/10/31 08:39:13]

BTW (this is not for this review) this |root| is guaranteed
non-null (L2376), so the first check is useless.

-          parentSlot.enqueueSlotChangeEvent();
+          parentSlot.didSlotChange(slotChangeType);
       }
     }
   }
 }
 
 DEFINE_TRACE(Node) {
   visitor->trace(m_parentOrShadowHostNode);
   visitor->trace(m_previous);
   visitor->trace(m_next);
   // rareData() and m_data.m_layoutObject share their storage. We have to trace
@@ skipping 78 matching lines @@
   if (node) {
     std::stringstream stream;
     node->printNodePathTo(stream);
     LOG(INFO) << stream.str();
   } else {
     LOG(INFO) << "Cannot showNodePath for <null>";
   }
 }
 
 #endif