(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..0116ac7644a6337f8eb98a44c54728d0679cbf47 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);
 }
@@ -1311,11 +1322,32 @@ void Document::setTitleElement(Element* titleElement)
             m_titleElement = Traversal<HTMLTitleElement>::firstWithin(*this);
         } else if (isSVGDocument()) {
             m_titleElement = Traversal<SVGTitleElement>::firstWithin(*this);
+            if (!m_titleElement)
+                m_titleElement = titleElement;
         }
     } else {
         m_titleElement = titleElement;
     }
 
+    if (!m_titleElement)

[hyunjunekim2, 2016/03/10 15:00:44]

Moved it.

+        return;
+
+    if (isSVGSVGElement(documentElement()) && documentElement() == m_titleElement->parentNode()) {
+        // If the root element is an svg element in the SVG namespace, then let value be the child

[fs, 2016/03/10 14:41:47]

Maybe you'd be better served to just fold this logic into the above block. Then
hopefully the comments could be paired with reasonably corresponding code and
thus make more sense. Then maybe the code could be written in a more "forward"
way, i.e maybe like:

// If the root element is an svg element in the SVG namespace, ...
if (isSVGSVGElement(documentElement())) {
    m_titleElement = Traversal<SVGTitleElement>::firstChild(*documentElement());
} else {
    m_titleElement = Traversal<HTMLTitleElement>::firstWithin(*this);
}

or whatever.

[hyunjunekim2, 2016/03/10 15:00:44]

Done.

+        // text content of the first title element in the SVG namespace that is a child of the root
+        // element.
+        if (!isSVGTitleElement(m_titleElement)) {
+            m_titleElement = nullptr;
+            return;
+        }
+    } else {
+        // Otherwise, let value be the child text content of the title element.

[fs, 2016/03/10 14:41:47]

This comment is very confusing together with the code that follows - i.e it's
very hard to connect the two.

[hyunjunekim2, 2016/03/10 15:00:44]

Done.

+        if (isSVGTitleElement(m_titleElement)) {
+            m_titleElement = nullptr;
+            return;
+        }
+    }
+
     if (isHTMLTitleElement(m_titleElement))
         updateTitle(toHTMLTitleElement(m_titleElement)->text());
     else if (isSVGTitleElement(m_titleElement))