Node.prototype.baseURI should not be nullable

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.
@@ skipping 3390 matching lines @@
   if (!EqualIgnoringFragmentIdentifier(old_base_url, base_url_)) {
     // Base URL change changes any relative visited links.
     // FIXME: There are other URLs in the tree that would need to be
     // re-evaluated on dynamic base URL change. Style should be invalidated too.
     for (HTMLAnchorElement& anchor :
          Traversal<HTMLAnchorElement>::StartsAfter(*this))
       anchor.InvalidateCachedVisitedLinkHash();
   }
 }
 
+const KURL& Document::BaseURL() const {
+  if (!base_url_.IsNull())
+    return base_url_;
+  return BlankURL();
+}
+
 void Document::SetBaseURLOverride(const KURL& url) {
   base_url_override_ = url;
   UpdateBaseURL();
 }
 
 void Document::ProcessBaseElement() {
   UseCounter::Count(*this, UseCounter::kBaseElement);
 
   // Find the first href attribute in a base element and the first target
   // attribute in a base element.
@@ skipping 3244 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (blink::Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->Url().GetString().Utf8().Data());
 }
 #endif