Extract a DOMWindow interface from LocalDOMWindow and use it in the idl.

Source/core/frame/LocalFrame.h

Index: Source/core/frame/LocalFrame.h
diff --git a/Source/core/frame/LocalFrame.h b/Source/core/frame/LocalFrame.h
index 419ad462e4f2a36ccbfe49bf964e6d9e18d4e00e..b3dc2904b1ac5b6ed14c9e569cb4d604124ed9b7 100644
--- a/Source/core/frame/LocalFrame.h
+++ b/Source/core/frame/LocalFrame.h
@@ -55,6 +55,7 @@ namespace blink {
     class InputMethodController;
     class IntPoint;
     class IntSize;
+    class LocalDOMWindow;
     class Node;
     class Range;
     class RenderView;
@@ -79,7 +80,7 @@ namespace blink {
         virtual ~LocalFrame();
         virtual void trace(Visitor*) override;
         virtual bool isLocalFrame() const override { return true; }
-        virtual LocalDOMWindow* domWindow() const override;
+        virtual DOMWindow* domWindow() const override;
         virtual void navigate(Document& originDocument, const KURL&, bool lockBackForwardList) override;
         virtual void detach() override;
         virtual void disconnectOwnerElement() override;
@@ -89,6 +90,7 @@ namespace blink {
 
         void willDetachFrameHost();
 
+        LocalDOMWindow* localDOMWindow() const;
         void setDOMWindow(PassRefPtrWillBeRawPtr<LocalDOMWindow>);
         FrameView* view() const;
         Document* document() const;
@@ -217,6 +219,11 @@ namespace blink {
         m_loader.init();
     }
 
+    inline LocalDOMWindow* LocalFrame::localDOMWindow() const
+    {
+        return m_domWindow.get();
+    }
+
     inline FrameLoader& LocalFrame::loader() const
     {
         return m_loader;