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

webkit/plugins/npapi/webplugin_impl.cc

 // 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.
 
 #include "webkit/plugins/npapi/webplugin_impl.h"
 
 #include "base/logging.h"
 #include "base/memory/linked_ptr.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
@@ skipping 714 matching lines @@
 
   WebCookieJar* cookie_jar = page_delegate_->GetCookieJar();
   if (!cookie_jar) {
     DLOG(WARNING) << "No cookie jar!";
     return std::string();
   }
 
   return UTF16ToUTF8(cookie_jar->cookies(url, first_party_for_cookies));
 }
 
-void WebPluginImpl::OnMissingPluginStatus(int status) {
-  NOTREACHED();
-}
-
 void WebPluginImpl::URLRedirectResponse(bool allow, int resource_id) {
   for (size_t i = 0; i < clients_.size(); ++i) {
     if (clients_[i].id == static_cast<unsigned long>(resource_id)) {
       if (clients_[i].loader.get()) {
         if (allow) {
           clients_[i].loader->setDefersLoading(false);
         } else {
           clients_[i].loader->cancel();
           clients_[i].client->DidFail();
         }
@@ skipping 614 matching lines @@
       webframe_->setReferrerForRequest(*request, plugin_url_);
       break;
 
     default:
       break;
   }
 }
 
 }  // namespace npapi
 }  // namespace webkit