Use PluginPrefs in ChromePluginServiceFilter to check whether a plugin is enabled.

content/renderer/webplugin_delegate_proxy.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 "content/renderer/webplugin_delegate_proxy.h"
 
 #if defined(TOOLKIT_USES_GTK)
 #include <gtk/gtk.h>
 #endif
 
@@ skipping 265 matching lines @@
 #endif
 
 bool WebPluginDelegateProxy::Initialize(
     const GURL& url,
     const std::vector<std::string>& arg_names,
     const std::vector<std::string>& arg_values,
     webkit::npapi::WebPlugin* plugin,
     bool load_manually) {
   IPC::ChannelHandle channel_handle;
   if (!RenderThread::current()->Send(new ViewHostMsg_OpenChannelToPlugin(
-          render_view_->routing_id(), url, mime_type_, &channel_handle,
-          &info_))) {
+          render_view_->routing_id(), url, page_url_, mime_type_,
+          &channel_handle, &info_))) {
     return false;
   }
 
   if (channel_handle.name.empty()) {
     // We got an invalid handle.  Either the plugin couldn't be found (which
     // shouldn't happen, since if we got here the plugin should exist) or the
     // plugin crashed on initialization.
     if (!info_.path.empty()) {
       render_view_->PluginCrashed(info_.path);
 
@@ skipping 1092 matching lines @@
 }
 #endif
 
 void WebPluginDelegateProxy::OnURLRedirectResponse(bool allow,
                                                    int resource_id) {
   if (!plugin_)
     return;
 
   plugin_->URLRedirectResponse(allow, resource_id);
 }