Create a ProfileDependencyManager to order ProfileKeyedService destruction.

chrome/browser/profiles/profile_keyed_service_factory.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 CHROME_BROWSER_PROFILES_PROFILE_KEYED_SERVICE_FACTORY_H_
+#define CHROME_BROWSER_PROFILES_PROFILE_KEYED_SERVICE_FACTORY_H_
+
+#include <map>
+
+class Profile;
+class ProfileDependencyManager;
+class ProfileKeyedService;
+
+// Base class for Factories that take a Profile object and return some service
+// on a one-to-one mapping. Each factory that derives from this class *must*
+// be a Singleton (only unit tests don't do that). See ThemeServiceFactory as
+// an example of how to derive from this class.
+//
+// We do this because services depend on each other and we need to control
+// shutdown/destruction order. In each derived classes' constructors, the
+// implementors must explicitly state which services are depended on.
+class ProfileKeyedServiceFactory {
+ protected:
+  friend class ProfileDependencyManager;
+  friend class ProfileDependencyManagerUnittests;
+
+  // ProfileKeyedServiceFactories must communicate with a
+  // ProfileDependencyManager. For all non-test code, write your subclass
+  // constructors like this:
+  //
+  //   MyServiceFactory::MyServiceFactory()
+  //     : ProfileKeyedServiceFactory(
+  //         ProfileDependencyManager::GetInstance())
+  //   {}
+  explicit ProfileKeyedServiceFactory(ProfileDependencyManager* manager);
+  virtual ~ProfileKeyedServiceFactory();
+
+  // Common implementation that maps |profile| to some service object. Deals
+  // with incognito profiles per subclass instructions with
+  // ServiceActiveInIncognito().
+  ProfileKeyedService* GetServiceForProfile(Profile* profile);
+
+  // The main public interface for declaring dependencies between services
+  // created by factories.
+  void DependsOn(ProfileKeyedServiceFactory* rhs);
+
+  // Maps |profile| to |provider| with debug checks to prevent duplication.
+  void Associate(Profile* profile, ProfileKeyedService* service);
+
+  // Returns a new instance of the service, casted to void* for our common
+  // storage.
+  virtual ProfileKeyedService* BuildServiceInstanceFor(
+      Profile* profile) const = 0;
+
+  // By default, if we are asked for a service with an Incognito profile, we
+  // pass back NULL. To redirect to the Incognito's original profile or to
+  // create another instance, even for Incognito windows, override one of the
+  // following methods:
+  virtual bool ServiceRedirectedInIncognito();
+  virtual bool ServiceHasOwnInstanceInIncognito();
+
+  // A helper object actually listens for notifications about Profile
+  // destruction, calculates the order in which things are destroyed and then
+  // does a two pass shutdown.
+  //
+  // First, ProfileShutdown() is called on every ServiceFactory and will
+  // usually call ProfileKeyedService::Shutdown(), which gives each
+  // ProfileKeyedService a chance to remove dependencies on other services that
+  // it may be holding.
+  //
+  // Secondly, ProfileDestroyed() is called on every ServiceFactory and the
+  // default implementation removes it from |mapping_| and deletes the pointer.
+  virtual void ProfileShutdown(Profile* profile);
+  virtual void ProfileDestroyed(Profile* profile);
+
+ private:
+  // The mapping between a Profile and its service.
+  std::map<Profile*, ProfileKeyedService*> mapping_;
+
+  // Which ProfileDependencyManager we should communicate with. In real code,
+  // this will always be ProfileDependencyManager::GetInstance(), but unit
+  // tests will want to use their own copy.
+  ProfileDependencyManager* dependency_manager_;
+};
+
+#endif  // CHROME_BROWSER_PROFILES_PROFILE_KEYED_SERVICE_FACTORY_H_