Clear child FrameNavigationEntries if a history navigation redirects.

content/browser/frame_host/navigation_entry_impl.h

 // Copyright 2013 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_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_
 
 #include <stdint.h>
 
 #include "base/macros.h"
@@ skipping 199 matching lines @@
       const GURL& url,
       const Referrer& referrer,
       const PageState& page_state,
       const std::string& method,
       int64_t post_id);
 
   // Returns the FrameNavigationEntry corresponding to |frame_tree_node|, if
   // there is one in this NavigationEntry.
   FrameNavigationEntry* GetFrameEntry(FrameTreeNode* frame_tree_node) const;
 
+  // Removes subframe FrameNavigationEntries below the item corresponding to
+  // |frame_tree_node| (if any).  This is necessary after server redirects
+  // during session history navigations, when the child items no longer apply.
+  void ClearChildren(FrameTreeNode* frame_tree_node);
+
   void set_unique_id(int unique_id) {
     unique_id_ = unique_id;
   }
 
   // The SiteInstance represents which pages must share processes. This is a
   // reference counted pointer to a shared SiteInstance.
   //
   // Note that the SiteInstance should usually not be changed after it is set,
   // but this may happen if the NavigationEntry was cloned and needs to use a
   // different SiteInstance.
@@ skipping 276 matching lines @@
   // persisted, unless specific data is taken out/put back in at save/restore
   // time (see TabNavigation for an example of this).
   std::map<std::string, base::string16> extra_data_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationEntryImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_IMPL_H_