Use an open shadow root in <use>

third_party/WebKit/Source/core/svg/SVGUseElement.cpp

Index: third_party/WebKit/Source/core/svg/SVGUseElement.cpp
diff --git a/third_party/WebKit/Source/core/svg/SVGUseElement.cpp b/third_party/WebKit/Source/core/svg/SVGUseElement.cpp
index fe8395d9c685a788366f03faa7439430b2ec6fff..d03b93b53fe1738e41f619eb46a1454e02b114c8 100644
--- a/third_party/WebKit/Source/core/svg/SVGUseElement.cpp
+++ b/third_party/WebKit/Source/core/svg/SVGUseElement.cpp
@@ -74,9 +74,9 @@ inline SVGUseElement::SVGUseElement(Document& document)
 
 SVGUseElement* SVGUseElement::create(Document& document)
 {
-    // Always build a user agent #shadow-root for SVGUseElement.
+    // Always build a closed #shadow-root for SVGUseElement.
     SVGUseElement* use = new SVGUseElement(document);
-    use->ensureUserAgentShadowRoot();
+    use->ensureShadow().addShadowRoot(*use, ShadowRootType::Open);
     return use;
 }
 
@@ -302,7 +302,7 @@ void SVGUseElement::clearShadowTree()
     clearInstanceRoot();
 
     // FIXME: We should try to optimize this, to at least allow partial reclones.
-    if (ShadowRoot* shadowTreeRootElement = userAgentShadowRoot())
+    if (ShadowRoot* shadowTreeRootElement = openShadowRoot())
         shadowTreeRootElement->removeChildren(OmitSubtreeModifiedEvent);
 
     removeAllOutgoingReferences();
@@ -437,7 +437,7 @@ void SVGUseElement::buildShadowAndInstanceTree(SVGElement& target)
     // Clone the target subtree into the shadow tree, not handling <use> and <symbol> yet.
     Element* instanceRoot = createInstanceTree(target);
     m_targetElementInstance = toSVGElement(instanceRoot);
-    ShadowRoot* shadowTreeRootElement = userAgentShadowRoot();
+    ShadowRoot* shadowTreeRootElement = openShadowRoot();
     shadowTreeRootElement->appendChild(instanceRoot);
 
     addReferencesToFirstDegreeNestedUseElements(target);
@@ -506,7 +506,7 @@ void SVGUseElement::toClipPath(Path& path) const
 
 SVGGraphicsElement* SVGUseElement::visibleTargetGraphicsElementForClipping() const
 {
-    Node* n = userAgentShadowRoot()->firstChild();
+    Node* n = openShadowRoot()->firstChild();
     if (!n || !n->isSVGElement())
         return nullptr;
 
@@ -550,7 +550,7 @@ void SVGUseElement::addReferencesToFirstDegreeNestedUseElements(SVGElement& targ
 
 void SVGUseElement::cloneNonMarkupEventListeners()
 {
-    for (SVGElement& element : Traversal<SVGElement>::descendantsOf(*userAgentShadowRoot())) {
+    for (SVGElement& element : Traversal<SVGElement>::descendantsOf(*openShadowRoot())) {
         if (EventTargetData* data = element.correspondingElement()->eventTargetData())
             data->eventListenerMap.copyEventListenersNotCreatedFromMarkupToTarget(&element);
     }
@@ -604,7 +604,7 @@ bool SVGUseElement::expandUseElementsInShadowTree()
     // contains <use> tags, we'd miss them. So once we're done with setting up the
     // actual shadow tree (after the special case modification for svg/symbol) we have
     // to walk it completely and expand all <use> elements.
-    ShadowRoot* shadowRoot = userAgentShadowRoot();
+    ShadowRoot* shadowRoot = openShadowRoot();
     for (SVGUseElement* use = Traversal<SVGUseElement>::firstWithin(*shadowRoot); use; ) {
         ASSERT(!use->resourceIsStillLoading());
 
@@ -742,7 +742,7 @@ bool SVGUseElement::resourceIsValid() const
 
 bool SVGUseElement::instanceTreeIsLoading() const
 {
-    for (const SVGUseElement& useElement : Traversal<SVGUseElement>::descendantsOf(*userAgentShadowRoot())) {
+    for (const SVGUseElement& useElement : Traversal<SVGUseElement>::descendantsOf(*openShadowRoot())) {
         if (useElement.resourceIsStillLoading())
             return true;
     }