Make a microtask of distribution recalc happen only when ShadowDOMV1 flag is enabled.

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/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 68 matching lines @@
 #include "core/frame/LocalFrame.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/html/HTMLSlotElement.h"
 #include "core/input/EventHandler.h"
 #include "core/layout/LayoutBox.h"
 #include "core/page/ContextMenuController.h"
 #include "core/page/Page.h"
 #include "core/svg/graphics/SVGImage.h"
 #include "platform/EventDispatchForbiddenScope.h"
+#include "platform/RuntimeEnabledFeatures.h"
 #include "platform/TraceEvent.h"
 #include "platform/TracedValue.h"
 #include "wtf/HashSet.h"
 #include "wtf/Partitions.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/Vector.h"
 #include "wtf/text/CString.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace blink {
@@ skipping 585 matching lines @@
 {
     ScriptForbiddenScope forbidScriptDuringRawIteration;
     for (Node* node = parentOrShadowHostNode(); node && !node->childNeedsStyleInvalidation(); node = node->parentOrShadowHostNode())
         node->setChildNeedsStyleInvalidation();
     document().scheduleLayoutTreeUpdateIfNeeded();
 }
 
 void Node::markAncestorsWithChildNeedsDistributionRecalc()
 {
     ScriptForbiddenScope forbidScriptDuringRawIteration;
-    if (inDocument() && !document().childNeedsDistributionRecalc()) {
+    if (RuntimeEnabledFeatures::shadowDOMV1Enabled() && inDocument() && !document().childNeedsDistributionRecalc()) {
         // TODO(hayato): Support a non-document composed tree.
         // TODO(hayato): Enqueue a task only if a 'slotchange' event listner is registered in the document composed tree.
         Microtask::enqueueMicrotask(WTF::bind(&Document::updateDistribution, PassRefPtrWillBeRawPtr<Document>(&document())));
     }
     for (Node* node = this; node && !node->childNeedsDistributionRecalc(); node = node->parentOrShadowHostNode())
         node->setChildNeedsDistributionRecalc();
     document().scheduleLayoutTreeUpdateIfNeeded();
 }
 
 inline void Node::setStyleChange(StyleChangeType changeType)
@@ skipping 1726 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif