Browser Plugin: Implement CanGoBack/CanGoForward

content/common/browser_plugin_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.
 
 // Multiply-included message header, no traditional include guard.
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/process.h"
@@ skipping 117 matching lines @@
 // A embedder sends this message to the browser when it wants
 // to resize a guest plugin container so that the guest is relaid out
 // according to the new size.
 IPC_SYNC_MESSAGE_ROUTED2_0(BrowserPluginHostMsg_ResizeGuest,
                            int /* instance_id*/,
                            BrowserPluginHostMsg_ResizeGuest_Params)
 
 // -----------------------------------------------------------------------------
 // These messages are from the browser process to the embedder.
 
+// When the guest navigates any of its frames, it reports to the browser plugin
+// the current state of navigation history so that that information can be
+// queried from Javascript.
+IPC_MESSAGE_CONTROL3(BrowserPluginMsg_NavigationStateUpdate,
+                     int /* instance_id */,
+                     bool /* current_entry_index */,
+                     int /* entry_count */)
+
+
 // When the guest begins to load a page, the browser process informs the
 // embedder through the BrowserPluginMsg_LoadStart message.
 IPC_MESSAGE_CONTROL3(BrowserPluginMsg_LoadStart,
                      int /* instance_id */,
                      GURL /* url */,
                      bool /* is_top_level */)
 
 // If the guest fails to commit a page load then it will inform the
 // embedder through the BrowserPluginMsg_LoadAbort. A description
 // of the error will be stored in |type|.  The list of known error
@@ skipping 70 matching lines @@
 IPC_MESSAGE_CONTROL2(BrowserPluginMsg_ShouldAcceptTouchEvents,
                      int /* instance_id */,
                      bool /* accept */)
 
 // The guest has damage it wants to convey to the embedder so that it can
 // update its backing store.
 IPC_MESSAGE_CONTROL3(BrowserPluginMsg_UpdateRect,
                      int /* instance_id */,
                      int /* message_id */,
                      BrowserPluginMsg_UpdateRect_Params)