Change the type of a SVG <use> element's shadow tree from "user agent" to "closed"

third_party/WebKit/Source/core/layout/HitTestResult.cpp

 /*
  * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 151 matching lines @@
       m_innerPossiblyPseudoNode->getPseudoId() == PseudoIdBefore)
     return mostForwardCaretPosition(
         Position(m_innerNode, PositionAnchorType::BeforeChildren));
   return layoutObject->positionForPoint(localPoint());
 }
 
 LayoutObject* HitTestResult::layoutObject() const {
   return m_innerNode ? m_innerNode->layoutObject() : 0;
 }
 
-void HitTestResult::setToShadowHostIfInUserAgentShadowRoot() {
+void HitTestResult::setToShadowHostIfInRestrictedShadowRoot() {
   Node* node = innerNode();
   if (!node)
     return;
 
   ShadowRoot* containingShadowRoot = node->containingShadowRoot();
   Element* shadowHost = nullptr;
 
+  // Consider a closed shadow tree of SVG's <use> element as a special
+  // case so that a toolip title in the shadow tree works.
   while (containingShadowRoot &&
-         containingShadowRoot->type() == ShadowRootType::UserAgent) {
+         (containingShadowRoot->type() == ShadowRootType::UserAgent ||
+          isSVGUseElement(containingShadowRoot->host()))) {
     shadowHost = &containingShadowRoot->host();
     containingShadowRoot = shadowHost->containingShadowRoot();
+    setInnerNode(node->ownerShadowHost());
   }
 
   if (shadowHost)
     setInnerNode(shadowHost);
 }
 
 HTMLAreaElement* HitTestResult::imageAreaForImage() const {
   ASSERT(m_innerNode);
   HTMLImageElement* imageElement = nullptr;
   if (isHTMLImageElement(m_innerNode)) {
@@ skipping 318 matching lines @@
   else if (isHTMLMapElement(m_innerNode))
     imageMapImageElement = toHTMLMapElement(m_innerNode)->imageElement();
 
   if (!imageMapImageElement)
     return m_innerNode.get();
 
   return imageMapImageElement;
 }
 
 }  // namespace blink