Add Blink APIs for frame tree mirroring.

Source/web/WebLocalFrameImpl.h

Index: Source/web/WebLocalFrameImpl.h
diff --git a/Source/web/WebLocalFrameImpl.h b/Source/web/WebLocalFrameImpl.h
index 8b360b622fddef5aab063d308aedea1dba383d84..3b431ba860298ae5efb6e36666f38df86830018c 100644
--- a/Source/web/WebLocalFrameImpl.h
+++ b/Source/web/WebLocalFrameImpl.h
@@ -103,6 +103,7 @@ public:
     virtual bool hasVerticalScrollbar() const OVERRIDE;
     virtual WebView* view() const OVERRIDE;
     virtual void setOpener(WebFrame*) OVERRIDE;
+    virtual void initializeAsMainFrame(WebView*) OVERRIDE;
     virtual void appendChild(WebFrame*) OVERRIDE;
     virtual void removeChild(WebFrame*) OVERRIDE;
     virtual WebFrame* traversePrevious(bool wrap) const OVERRIDE;
@@ -237,9 +238,6 @@ public:
     static WebLocalFrameImpl* create(WebFrameClient*);
     virtual ~WebLocalFrameImpl();
 
-    // Called by the WebViewImpl to initialize the main frame for the page.
-    void initializeAsMainFrame(WebCore::Page*);
-
     PassRefPtr<WebCore::LocalFrame> createChildFrame(
         const WebCore::FrameLoadRequest&, WebCore::HTMLFrameOwnerElement*);
 
@@ -313,6 +311,8 @@ public:
     // Invalidates both content area and the scrollbar.
     void invalidateAll() const;
 
+    void initializeAsChildFrame(WebCore::FrameHost*, WebCore::FrameOwner*, const AtomicString& name, const AtomicString& fallbackName);
+
 private:
     friend class FrameLoaderClientImpl;