Refactor frame navigation/detach state cleanup to be more sane.

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 1bbbc0f2acd06a375df60a5dcb7dd3306a855d46..681db607543d514f072c5926c7719cc6cfde918a 100644
--- a/Source/core/frame/LocalFrame.h
+++ b/Source/core/frame/LocalFrame.h
@@ -189,8 +189,6 @@ namespace blink {
 
         String localLayerTreeAsText(unsigned flags) const;
 
-        void detachView();
-
         // Paints the area for the given rect into a DragImage, with the given displayItemClient id attached.
         // The rect is in the coordinate space of the frame.
         PassOwnPtr<DragImage> paintIntoDragImage(const DisplayItemClientWrapper&, DisplayItem::Type, RespectImageOrientationEnum shouldRespectImageOrientation, IntRect paintingRect);