Fix regression with back-button not working on prerendered and instant pages.

content/renderer/render_view.h

 // Copyright (c) 2011 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_RENDERER_RENDER_VIEW_H_
 #define CONTENT_RENDERER_RENDER_VIEW_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 829 matching lines @@
   void OnSetZoomLevelForLoadingURL(const GURL& url, double zoom_level);
   void OnShouldClose();
   void OnStop();
   void OnStopFinding(const ViewMsg_StopFinding_Params& params);
   void OnSwapOut(const ViewMsg_SwapOut_Params& params);
   void OnThemeChanged();
   void OnUndo();
   void OnUpdateTargetURLAck();
   void OnUpdateWebPreferences(const WebPreferences& prefs);
   void OnUpdateRemoteAccessClientFirewallTraversal(const std::string& policy);
+  void OnSetHistoryLengthAndClear(int history_length);
 
 #if defined(OS_MACOSX)
   void OnWindowFrameChanged(const gfx::Rect& window_frame,
                             const gfx::Rect& view_frame);
   void OnSelectPopupMenuItem(int selected_index);
 #endif
   void OnZoom(PageZoom::Function function);
 
   // Adding a new message handler? Please add it in alphabetical order above
   // and put it in the same position in the .cc file.
@@ skipping 348 matching lines @@
   // bunch of stuff, you should probably create a helper class and put your
   // data and methods on that to avoid bloating RenderView more.  You can use
   // the Observer interface to filter IPC messages and receive frame change
   // notifications.
   // ---------------------------------------------------------------------------
 
   DISALLOW_COPY_AND_ASSIGN(RenderView);
 };
 
 #endif  // CONTENT_RENDERER_RENDER_VIEW_H_