Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/public/web/WebFrame.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 163 matching lines @@
 
   // Returns true if the contents (minus scrollbars) has non-zero area.
   virtual bool HasVisibleContent() const = 0;
 
   // Returns the visible content rect (minus scrollbars, in absolute coordinate)
   virtual WebRect VisibleContentRect() const = 0;
 
   virtual bool HasHorizontalScrollbar() const = 0;
   virtual bool HasVerticalScrollbar() const = 0;
 
+  // Whether to collapse the frame's owner element in the embedder document,
+  // that is, to remove it from the layout as if it did not exist. Only works
+  // for <iframe> owner elements.
+  virtual void Collapse(bool) = 0;
+
   // Hierarchy ----------------------------------------------------------
 
   // Returns the containing view.
   virtual WebView* View() const = 0;
 
   // Returns the frame that opened this frame or 0 if there is none.
   BLINK_EXPORT WebFrame* Opener() const;
 
   // Sets the frame that opened this one or 0 if there is none.
   BLINK_EXPORT void SetOpener(WebFrame*);
@@ skipping 264 matching lines @@
   WebFrame* first_child_;
   WebFrame* last_child_;
 
   WebFrame* opener_;
   std::unique_ptr<OpenedFrameTracker> opened_frame_tracker_;
 };
 
 }  // namespace blink
 
 #endif