(Re-commit) Fix SVGDocument return title that is not a child of the root element

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

 /*
  * Copyright (C) 2004, 2005 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  *
  * 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "core/svg/SVGTitleElement.h"
 
 #include "core/SVGNames.h"
+#include "core/dom/ChildListMutationScope.h"
 #include "core/dom/Document.h"
+#include "core/dom/Text.h"
 
 namespace blink {
 
 inline SVGTitleElement::SVGTitleElement(Document& document)
     : SVGElement(SVGNames::titleTag, document)
+    , m_ignoreTitleUpdatesWhenChildrenChange(false)
 {
 }
 
 DEFINE_NODE_FACTORY(SVGTitleElement)
 
 Node::InsertionNotificationRequest SVGTitleElement::insertedInto(ContainerNode* rootParent)
 {
     SVGElement::insertedInto(rootParent);
     if (!rootParent->inDocument())
         return InsertionDone;
     if (hasChildren() && document().isSVGDocument())
         document().setTitleElement(this);
     return InsertionDone;
 }
 
 void SVGTitleElement::removedFrom(ContainerNode* rootParent)
 {
     SVGElement::removedFrom(rootParent);
     if (rootParent->inDocument() && document().isSVGDocument())
         document().removeTitle(this);
 }
 
 void SVGTitleElement::childrenChanged(const ChildrenChange& change)
 {
     SVGElement::childrenChanged(change);
-    if (inDocument() && document().isSVGDocument())
+    if (inDocument() && document().isSVGDocument() && !m_ignoreTitleUpdatesWhenChildrenChange)
         document().setTitleElement(this);
 }
 
+void SVGTitleElement::setText(const String& value)
+{
+    RefPtrWillBeRawPtr<Node> protectFromMutationEvents(this);
+    ChildListMutationScope mutation(*this);
+
+    {
+        // Avoid calling Document::setTitleElement() during intermediate steps.
+        TemporaryChange<bool> inhibitTitleUpdateScope(m_ignoreTitleUpdatesWhenChildrenChange, !value.isEmpty());
+        removeChildren(OmitSubtreeModifiedEvent);
+    }
+
+    if (!value.isEmpty())
+        appendChild(document().createTextNode(value.impl()), IGNORE_EXCEPTION);
+}
+
 } // namespace blink