Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

content/public/browser/navigation_throttle.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_
 #define CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_
 
 #include "content/common/content_export.h"
 
 namespace content {
@@ skipping 22 matching lines @@
     // like the request was never made.
     CANCEL_AND_IGNORE,
 
     // Blocks a navigation due to rules asserted before the request is made.
     // This can only be returned from WillStartRequest and also from
     // WillRedirectRequest when PlzNavigate is enabled. This will result in an
     // error page for net::ERR_BLOCKED_BY_CLIENT being loaded in the frame that
     // is navigated.
     BLOCK_REQUEST,
 
+    // Blocks a navigation taking place in a subframe, and collapses the frame
+    // owner element in the parent document (i.e. removes it from the layout).
+    // This can only be returned from WillStartRequest, and also from
+    // WillRedirectRequest when PlzNavigate is enabled.
+    BLOCK_REQUEST_AND_COLLAPSE,
+
     // Blocks a navigation due to rules asserted by a response (for instance,
     // embedding restrictions like 'X-Frame-Options'). This result will only
     // be returned from WillProcessResponse.
     BLOCK_RESPONSE,
   };
 
   NavigationThrottle(NavigationHandle* navigation_handle);
   virtual ~NavigationThrottle();
 
   // Called when a network request is about to be made for this navigation.
@@ skipping 32 matching lines @@
   // navigation.
   NavigationHandle* navigation_handle() const { return navigation_handle_; }
 
  private:
   NavigationHandle* navigation_handle_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_NAVIGATION_THROTTLE_H_