Avoid stale navigation requests without excessive page id knowledge in the renderer process.

content/common/view_messages.h

 // 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.
 
 // IPC messages for page rendering.
 // Multiply-included message file, hence no include guard.
 
 #include "base/memory/shared_memory.h"
 #include "base/process/process.h"
 #include "base/strings/string16.h"
@@ skipping 535 matching lines @@
 IPC_MESSAGE_ROUTED1(ViewMsg_LockMouse_ACK,
                     bool /* succeeded */)
 // Tells the render side that the mouse has been unlocked.
 IPC_MESSAGE_ROUTED0(ViewMsg_MouseLockLost)
 
 // Sent by the browser when the parameters for vsync alignment have changed.
 IPC_MESSAGE_ROUTED2(ViewMsg_UpdateVSyncParameters,
                     base::TimeTicks /* timebase */,
                     base::TimeDelta /* interval */)
 
-// Sent to the RenderView when a new tab is swapped into an existing
-// tab and the histories need to be merged. The existing tab has a history of
-// |merged_history_length| which precedes the history of the new tab. All
-// page_ids >= |minimum_page_id| in the new tab are appended to the history.
-//
-// For example, suppose the history of page_ids in the new tab's RenderView
-// is [4 7 8]. This is merged into an existing tab with 3 history items, and
-// all pages in the new tab with page_id >= 7 are to be preserved.
-// The resulting page history is [-1 -1 -1 7 8].
-IPC_MESSAGE_ROUTED2(ViewMsg_SetHistoryLengthAndPrune,
-                    int, /* merge_history_length */
-                    int32 /* minimum_page_id */)
+// Sent when the history is altered outside of navigation. The history list was
+// reset to |history_length| length, and the offset was reset to be
+// |history_offset|.
+IPC_MESSAGE_ROUTED2(ViewMsg_SetHistoryOffsetAndLength,
+                    int /* history_offset */,
+                    int /* history_length */)
 
 // Tells the renderer to create a new view.
 // This message is slightly different, the view it takes (via
 // ViewMsg_New_Params) is the view to create, the message itself is sent as a
 // non-view control message.
 IPC_MESSAGE_CONTROL1(ViewMsg_New,
                      ViewMsg_New_Params)
 
 // Reply in response to ViewHostMsg_ShowView or ViewHostMsg_ShowWidget.
 // similar to the new command, but used when the renderer created a view
@@ skipping 1085 matching lines @@
 // Since the browser keeps handles to the allocated transport DIBs, this
 // message is sent to tell the browser that it may release them when the
 // renderer is finished with them.
 IPC_MESSAGE_CONTROL1(ViewHostMsg_FreeTransportDIB,
                      TransportDIB::Id /* DIB id */)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform
 // independent ViewMsg, then ifdefs for platform specific ViewMsg, then platform
 // independent ViewHostMsg, then ifdefs for platform specific ViewHostMsg.