[WIP] Adding support for <iframe>s to slimming paint.

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 24 matching lines @@
 
 namespace blink {
 
 class ChromeClient;
 class Document;
 class FrameClient;
 class FrameHost;
 class FrameOwner;
 class HTMLFrameOwnerElement;
 class LocalDOMWindow;
+class LocalFrame;
 class KURL;
 class Page;
 class RenderPart;
 class Settings;
 class WebLayer;
 
 struct Referrer;
 
 class Frame : public RefCountedWillBeGarbageCollectedFinalized<Frame> {
 public:
@@ skipping 16 matching lines @@
     FrameClient* client() const;
 
     // NOTE: Page is moving out of Blink up into the browser process as
     // part of the site-isolation (out of process iframes) work.
     // FrameHost should be used instead where possible.
     Page* page() const;
     FrameHost* host() const; // Null when the frame is detached.
 
     bool isMainFrame() const;
     bool isLocalRoot() const;
+    LocalFrame* localRoot() const;
 
     FrameOwner* owner() const;
     void setOwner(FrameOwner* owner) { m_owner = owner; }
     HTMLFrameOwnerElement* deprecatedLocalOwner() const;
 
     FrameTree& tree() const;
     ChromeClient& chromeClient() const;
 
     RenderPart* ownerRenderer() const; // Renderer for the element that contains this frame.
 
@@ 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