Ensure that CopyStateFromAndPrune doesn't exceed kMaxSessionHistoryEntries.

content/browser/tab_contents/navigation_controller_impl.h

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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_TAB_CONTENTS_NAVIGATION_CONTROLLER_IMPL_H_
 #define CONTENT_BROWSER_TAB_CONTENTS_NAVIGATION_CONTROLLER_IMPL_H_
 #pragma once
 
 #include "build/build_config.h"
 #include "base/compiler_specific.h"
 #include "base/memory/linked_ptr.h"
@@ skipping 229 matching lines @@
 
   // Removes the entry at |index|, as long as it is not the current entry.
   void RemoveEntryAtIndexInternal(int index);
 
   // Discards the pending and transient entries.
   void DiscardNonCommittedEntriesInternal();
 
   // Discards the transient entry.
   void DiscardTransientEntry();
 
+  // If we have the maximum number of entries, remove the oldest one in
+  // preparation to add another.
+  void PruneOldestEntryIfFull();
+
   // Returns true if the navigation is redirect.
   bool IsRedirect(const ViewHostMsg_FrameNavigate_Params& params);
 
   // Returns true if the navigation is likley to be automatic rather than
   // user-initiated.
   bool IsLikelyAutoNavigation(base::TimeTicks now);
 
   // Inserts up to |max_index| entries from |source| into this. This does NOT
   // adjust any of the members that reference entries_
   // (last_committed_entry_index_, pending_entry_index_ or
@@ skipping 58 matching lines @@
   static size_t max_entry_count_for_testing_;
 
   // If a repost is pending, its type (RELOAD or RELOAD_IGNORING_CACHE),
   // NO_RELOAD otherwise.
   ReloadType pending_reload_;
 
   DISALLOW_COPY_AND_ASSIGN(NavigationControllerImpl);
 };
 
 #endif  // CONTENT_BROWSER_TAB_CONTENTS_NAVIGATION_CONTROLLER_IMPL_H_