Refactor PluginService to take PluginList as a dependency.

content/test/test_plugin_service.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_TEST_TEST_PLUGIN_SERVICE_H_
+#define CONTENT_TEST_TEST_PLUGIN_SERVICE_H_
+#pragma once
+
+#include "content/browser/plugin_service.h"
+
+namespace webkit {
+namespace npapi {
+class PluginList;
+}
+}
+
+// This class can be used in tests to bypass the actual plugin loading logic. It
+// is meant to be used in conjuction with MockPluginList and will perform a
+// synchronous load of plugins on the thread on which the GetPlugin* methods
+// were called. Note that the callbacks will still be run off the message loop.
+//
+// If you're wondering how this works in conjunction with the PluginService
+// singleton, the answer is to refactor your component to use dependency
+// injection to take an instance of PluginService, store it as a member, and
+// pass in an instance of this during tests.
+class TestPluginService : public PluginService {
+ public:
+  TestPluginService(webkit::npapi::PluginList* plugin_list);
+  virtual ~TestPluginService();
+
+  // PluginService:
+  virtual void GetPlugins(const GetPluginsCallback& cb) OVERRIDE;
+  virtual void GetPluginGroups(const GetPluginGroupsCallback& cb) OVERRIDE;
+};
+
+#endif  // CONTENT_TEST_TEST_PLUGIN_SERVICE_H_