FrameTree::Find only searches relative to local frames.

third_party/WebKit/Source/core/frame/LocalFrame.h

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999-2001 Lars Knoll <knoll@kde.org>
  *                     1999-2001 Antti Koivisto <koivisto@kde.org>
  *                     2000-2001 Simon Hausmann <hausmann@kde.org>
  *                     2000-2001 Dirk Mueller <mueller@kde.org>
  *                     2000 Stefan Schimanski <1Stein@gmx.de>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights
  * reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
@@ skipping 110 matching lines @@
   bool ShouldClose() override;
   SecurityContext* GetSecurityContext() const override;
   void PrintNavigationErrorMessage(const Frame&, const char* reason) override;
   void PrintNavigationWarning(const String&) override;
   bool PrepareForCommit() override;
   void DidChangeVisibilityState() override;
 
   void DetachChildren();
   void DocumentAttached();
 
+  Frame* FindFrameForNavigation(const AtomicString& name,
+                                LocalFrame& active_frame);
+
   // Note: these two functions are not virtual but intentionally shadow the
   // corresponding method in the Frame base class to return the
   // LocalFrame-specific subclass.
   LocalWindowProxy* WindowProxy(DOMWrapperWorld&);
   LocalDOMWindow* DomWindow() const;
   void SetDOMWindow(LocalDOMWindow*);
   LocalFrameView* View() const override;
   Document* GetDocument() const;
   void SetPagePopupOwner(Element&);
   Element* PagePopupOwner() const { return page_popup_owner_.Get(); }
@@ skipping 258 matching lines @@
   explicit ScopedFrameBlamer(LocalFrame*);
   ~ScopedFrameBlamer();
 
  private:
   Member<LocalFrame> frame_;
 };
 
 }  // namespace blink
 
 #endif  // LocalFrame_h