Use PostTaskAndReplyWithResult in plugin_service_impl.cc.

content/test/fake_plugin_service.cc

 // Copyright 2014 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 "build/build_config.h"
 #include "content/test/fake_plugin_service.h"
 
 namespace content {
 
 FakePluginService::FakePluginService() {
@@ skipping 31 matching lines @@
 bool FakePluginService::GetPluginInfoByPath(const base::FilePath& plugin_path,
                                             WebPluginInfo* info) {
   return false;
 }
 
 base::string16 FakePluginService::GetPluginDisplayNameByPath(
     const base::FilePath& path) {
   return base::string16();
 }
 
-void FakePluginService::GetPlugins(const GetPluginsCallback& callback) {
-}
+void FakePluginService::GetPlugins(GetPluginsCallback callback) {}
 
 PepperPluginInfo* FakePluginService::GetRegisteredPpapiPluginInfo(
     const base::FilePath& plugin_path) {
   return nullptr;
 }
 
 void FakePluginService::SetFilter(PluginServiceFilter* filter) {
 }
 
 PluginServiceFilter* FakePluginService::GetFilter() {
@@ skipping 19 matching lines @@
     std::vector<WebPluginInfo>* plugins) {
 }
 
 bool FakePluginService::PpapiDevChannelSupported(
     BrowserContext* browser_context,
     const GURL& document_url) {
   return false;
 }
 
 }  // namespace content