Generate FrameTree::uniqueName with a URL attribute value.

Source/core/page/FrameTree.h

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * 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
@@ skipping 17 matching lines @@
     class TreeScope;
 
     class FrameTree {
         WTF_MAKE_NONCOPYABLE(FrameTree);
     public:
         explicit FrameTree(LocalFrame* thisFrame);
         ~FrameTree();
 
         const AtomicString& name() const { return m_name; }
         const AtomicString& uniqueName() const { return m_uniqueName; }
-        void setName(const AtomicString&);
+        // If |name| is not empty, |fallbackName| is ignored. Otherwise,
+        // |fallbackName| is used as a source of uniqueName.
+        void setName(const AtomicString& name, const AtomicString& fallbackName = nullAtom);
 
         LocalFrame* parent() const;
         LocalFrame* top() const;
         LocalFrame* previousSibling() const;
         LocalFrame* nextSibling() const;
         LocalFrame* firstChild() const;
         LocalFrame* lastChild() const;
 
         bool isDescendantOf(const LocalFrame* ancestor) const;
         LocalFrame* traversePreviousWithWrap(bool) const;
@@ skipping 24 matching lines @@
     };
 
 } // namespace WebCore
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showFrameTree(const WebCore::LocalFrame*);
 #endif
 
 #endif // FrameTree_h