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

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 1269 matching lines @@
         m_title = canonicalizedTitle<UChar>(this, m_rawTitle);
 
     if (!m_frame || oldTitle == m_title)
         return;
     m_frame->loader().client()->dispatchDidReceiveTitle(m_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);
 }
 
 void Document::setTitleElement(Element* titleElement)
 {
     // Only allow the first title element to change the title -- others have no effect.
     if (m_titleElement && m_titleElement != titleElement) {
         if (isHTMLDocument() || isXHTMLDocument()) {
             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))
         updateTitle(toSVGTitleElement(m_titleElement)->textContent());
 }
 
 void Document::removeTitle(Element* titleElement)
 {
     if (m_titleElement != titleElement)
         return;
@@ skipping 4661 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::liveDocumentSet();
     fprintf(stderr, "There are %u documents currently alive:\n", set.size());
     for (Document* document : set)
         fprintf(stderr, "- Document %p URL: %s\n", document, document->url().getString().utf8().data());
 }
 #endif