Moved the following IPC messages used by the chrome NPAPI plugin installer out of content

content/plugin/webplugin_proxy.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_PLUGIN_WEBPLUGIN_PROXY_H_
 #define CONTENT_PLUGIN_WEBPLUGIN_PROXY_H_
 #pragma once
 
 #include <string>
 
@@ skipping 61 matching lines @@
   virtual void Invalidate();
   virtual void InvalidateRect(const gfx::Rect& rect);
   virtual NPObject* GetWindowScriptNPObject();
   virtual NPObject* GetPluginElement();
   virtual void SetCookie(const GURL& url,
                          const GURL& first_party_for_cookies,
                          const std::string& cookie);
   virtual std::string GetCookies(const GURL& url,
                                  const GURL& first_party_for_cookies);
 
-  virtual void OnMissingPluginStatus(int status);
   // class-specific methods
 
   // Returns a WebPluginResourceClient object given its id, or NULL if no
   // object with that id exists.
   webkit::npapi::WebPluginResourceClient* GetResourceClient(int id);
 
   // Returns the id of the renderer that contains this plugin.
   int GetRendererId();
 
   // Returns the id of the associated render view.
@@ skipping 170 matching lines @@
 
 #endif
 
   // Contains the routing id of the host render view.
   int host_render_view_routing_id_;
 
   ScopedRunnableMethodFactory<WebPluginProxy> runnable_method_factory_;
 };
 
 #endif  // CONTENT_PLUGIN_WEBPLUGIN_PROXY_H_