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

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

Index: third_party/WebKit/Source/core/dom/Document.cpp
diff --git a/third_party/WebKit/Source/core/dom/Document.cpp b/third_party/WebKit/Source/core/dom/Document.cpp
index 93a13ab219b2a1740691546634dd51c213453042..e3b138245dbd18a2d07896bd649e4b387e6a50d3 100644
--- a/third_party/WebKit/Source/core/dom/Document.cpp
+++ b/third_party/WebKit/Source/core/dom/Document.cpp
@@ -1287,18 +1287,29 @@ void Document::updateTitle(const String& title)
 void Document::setTitle(const String& title)
 {
     // Title set by JavaScript -- overrides any title elements.
-    if (!isHTMLDocument() && !isXHTMLDocument()) {
-        m_titleElement = nullptr;
-    } else if (!m_titleElement) {
-        HTMLElement* headElement = head();
-        if (!headElement)
-            return;
-        m_titleElement = HTMLTitleElement::create(*this);
-        headElement->appendChild(m_titleElement.get());
+    if (!m_titleElement) {
+        if (isHTMLDocument() || isXHTMLDocument()) {
+            HTMLElement* headElement = head();
+            if (!headElement)
+                return;
+            m_titleElement = HTMLTitleElement::create(*this);
+            headElement->appendChild(m_titleElement.get());
+        } else if (isSVGDocument()) {
+            Element* element = documentElement();
+            if (!isSVGSVGElement(element))
+                return;
+            m_titleElement = SVGTitleElement::create(*this);
+            element->insertBefore(m_titleElement.get(), element->firstChild());
+        }
+    } else {
+        if (!isHTMLDocument() && !isXHTMLDocument() && !isSVGDocument())
+            m_titleElement = nullptr;
     }
 
     if (isHTMLTitleElement(m_titleElement))
         toHTMLTitleElement(m_titleElement)->setText(title);
+    else if (isSVGTitleElement(m_titleElement))
+        toSVGTitleElement(m_titleElement)->setText(title);
     else
         updateTitle(title);
 }
@@ -1316,6 +1327,31 @@ void Document::setTitleElement(Element* titleElement)
         m_titleElement = titleElement;
     }
 
+    if (isSVGDocument()) {
+        // If the root element that is <svg> element in the svg namespace is not the parent of <title> element,
+        // ignore <title> element.
+        Node* parent = m_titleElement->parentNode();
+        while (parent) {
+            if (isSVGSVGElement(parent) && toSVGElement(parent)->isOutermostSVGSVGElement()) {
+                if (documentElement() != parent || m_titleElement->parentNode() != parent) {
+                    m_titleElement = nullptr;
+                    return;
+                }
+                break;
+            }
+            parent = parent->parentNode();
+        }
+
+        // If the root element is not <svg> element in the svg namespace and <title> element is in the svg namespace,
+        // or the root element is <svg> element in the svg namespace and <title> element is not in the svg namespace,
+        // ignore <title> element.
+        if ((!isSVGSVGElement(m_titleElement->parentNode()) && isSVGTitleElement(m_titleElement))
+            || (isSVGSVGElement(m_titleElement->parentNode()) && !isSVGTitleElement(m_titleElement))) {
+            m_titleElement = nullptr;
+            return;
+        }
+    }
+
     if (isHTMLTitleElement(m_titleElement))
         updateTitle(toHTMLTitleElement(m_titleElement)->text());
     else if (isSVGTitleElement(m_titleElement))