Simplify WindowProxy handoff in WebFrame::swap().

Source/core/frame/Frame.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)
  * Copyright (C) 2008 Eric Seidel <eric@webkit.org>
@@ skipping 92 matching lines @@
     virtual SecurityContext* securityContext() const = 0;
 
     Frame* findFrameForNavigation(const AtomicString& name, Frame& activeFrame);
     Frame* findUnsafeParentScrollPropagationBoundary();
 
     // This prepares the Frame for the next commit. It will detach children,
     // dispatch unload events, abort XHR requests and detach the document.
     // Returns true if the frame is ready to receive the next commit, or false
     // otherwise.
     virtual bool prepareForCommit() = 0;
-    void prepareSwapFrom(Frame*);
     void finishSwapFrom(Frame*);
 
     bool canNavigate(const Frame&);
     virtual void printNavigationErrorMessage(const Frame&, const char* reason) = 0;
 
     LayoutPart* ownerLayoutObject() const; // LayoutObject for the element that contains this frame.
 
     int64_t frameID() const { return m_frameID; }
 
     Settings* settings() const; // can be null
@@ skipping 36 matching lines @@
 {
     return m_treeNode;
 }
 
 // Allow equality comparisons of Frames by reference or pointer, interchangeably.
 DEFINE_COMPARISON_OPERATORS_WITH_REFERENCES_REFCOUNTED(Frame)
 
 } // namespace blink
 
 #endif // Frame_h