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

chrome/renderer/chrome_content_renderer_client.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 "chrome/renderer/chrome_content_renderer_client.h"
 
 #include <string>
 
 #include "base/command_line.h"
 #include "base/message_loop.h"
@@ skipping 274 matching lines @@
   webkit::npapi::WebPluginInfo info;
   GURL url(original_params.url);
   std::string orig_mime_type = original_params.mimeType.utf8();
   std::string actual_mime_type;
   render_view->Send(new ViewHostMsg_GetPluginInfo(
       render_view->routing_id(), url, frame->top()->document().url(),
       orig_mime_type, &found, &info, &actual_mime_type));
 
   if (!found)
     return NULL;
-  if (!webkit::npapi::IsPluginEnabled(info))
-    return NULL;
 
   *is_default_plugin =
     info.path.value() == webkit::npapi::kDefaultPluginLibraryName;
 
   if (orig_mime_type == actual_mime_type) {
     UMA_HISTOGRAM_ENUMERATION(kPluginTypeMismatch,
                               PLUGIN_TYPE_MISMATCH_NONE,
                               PLUGIN_TYPE_MISMATCH_NUM_EVENTS);
   } else if (orig_mime_type.empty()) {
     UMA_HISTOGRAM_ENUMERATION(kPluginTypeMismatch,
@@ skipping 391 matching lines @@
   if (spellcheck_.get())
     thread->RemoveObserver(spellcheck_.get());
   SpellCheck* new_spellcheck = new SpellCheck();
   if (spellcheck_provider_)
     spellcheck_provider_->SetSpellCheck(new_spellcheck);
   spellcheck_.reset(new_spellcheck);
   thread->AddObserver(new_spellcheck);
 }
 
 }  // namespace chrome