Fix app_shell shutdown crash due to BrowserContextKeyedServices

* Create ExtensionSystem and register its dependencies from the ExtensionsBrowserClient interface.
* Create and tear down BrowserContextKeyedServices using the dependency manager like you're supposed to do it.
* Don't register AppLoaderServiceFactory - we don't use it anymore.
* Remove the "custom instance" code to ExtensionSystem::Get() - it was kind of hacky.

BUG=none
TEST=Launch app_shell then close the window. No crash.

Review URL: https://codereview.chromium.org/118043003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244013 0039d316-1c4b-4281-b951-d872f2087c98

apps/shell/shell_browser_context.cc

@@ -4,25 +4,14 @@
 
 #include "apps/shell/shell_browser_context.h"
 
-#include "apps/app_load_service_factory.h"
-
-namespace {
-
-// See ChromeBrowserMainExtraPartsProfiles for details.
-void EnsureBrowserContextKeyedServiceFactoriesBuilt() {
-  apps::AppLoadServiceFactory::GetInstance();
-}
-
-}  // namespace
-
 namespace apps {
 
-// TODO(jamescook): Should this be an off-the-record context?
-// TODO(jamescook): Could initialize NetLog here to get logs from the networking
-// stack.
+// Create a normal recording browser context. If we used an incognito context
+// then app_shell would also have to create a normal context and manage both.
 ShellBrowserContext::ShellBrowserContext()
     : content::ShellBrowserContext(false, NULL) {
-  EnsureBrowserContextKeyedServiceFactoriesBuilt();
+  // TODO(jamescook): Could initialize NetLog here to get logs from the
+  // networking stack.
 }
 
 ShellBrowserContext::~ShellBrowserContext() {

apps/shell/shell_browser_main_parts.cc

@@ -13,9 +13,10 @@
 #include "base/files/file_path.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
-#include "chrome/browser/extensions/extension_system_factory.h"
+#include "chrome/browser/extensions/extension_system.h"
 #include "chrome/common/chrome_paths.h"
 #include "chromeos/chromeos_paths.h"
+#include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
 #include "content/public/common/result_codes.h"
 #include "extensions/common/extension_paths.h"
 #include "ui/aura/env.h"
@@ -27,8 +28,18 @@
 
 using content::BrowserContext;
 using extensions::Extension;
+using extensions::ExtensionSystem;
+using extensions::ShellExtensionSystem;
 
 namespace apps {
+namespace {
+
+void EnsureBrowserContextKeyedServiceFactoriesBuilt() {
+  // TODO(jamescook): Register additional BrowserContextKeyedService factories
+  // here. See ChromeBrowserMainExtraPartsProfiles for details.
+}
+
+}  // namespace
 
 ShellBrowserMainParts::ShellBrowserMainParts(
     const content::MainFunctionParams& parameters)
@@ -77,15 +88,16 @@ void ShellBrowserMainParts::PreMainMessageLoopRun() {
   extensions::ExtensionsClient::Set(extensions_client_.get());
 
   extensions_browser_client_.reset(
-      new ShellExtensionsBrowserClient(browser_context_.get()));
+      new extensions::ShellExtensionsBrowserClient(browser_context_.get()));
   extensions::ExtensionsBrowserClient::Set(extensions_browser_client_.get());
 
-  // TODO(jamescook): Initialize policy::ProfilePolicyConnector.
-
+  // Create our custom ExtensionSystem first because other
+  // BrowserContextKeyedServices depend on it.
   CreateExtensionSystem();
 
-  // TODO(jamescook): Create the rest of the services using
-  // BrowserContextDependencyManager::CreateBrowserContextServices.
+  EnsureBrowserContextKeyedServiceFactoriesBuilt();
+  BrowserContextDependencyManager::GetInstance()->CreateBrowserContextServices(
+      browser_context_.get());
 
   CreateRootWindow();
 
@@ -111,16 +123,13 @@ bool ShellBrowserMainParts::MainMessageLoopRun(int* result_code)  {
 
 void ShellBrowserMainParts::PostMainMessageLoopRun() {
   DestroyRootWindow();
-  // TODO(jamescook): Destroy the rest of the services with
-  // BrowserContextDependencyManager::DestroyBrowserContextServices.
+  BrowserContextDependencyManager::GetInstance()->DestroyBrowserContextServices(
+      browser_context_.get());
+  extension_system_ = NULL;
   extensions::ExtensionsBrowserClient::Set(NULL);
   extensions_browser_client_.reset();
   browser_context_.reset();
   aura::Env::DeleteInstance();
-
-  LOG(WARNING) << "-----------------------------------";
-  LOG(WARNING) << "app_shell is expected to crash now.";
-  LOG(WARNING) << "-----------------------------------";
 }
 
 void ShellBrowserMainParts::OnWindowTreeHostCloseRequested(
@@ -149,12 +158,8 @@ void ShellBrowserMainParts::DestroyRootWindow() {
 
 void ShellBrowserMainParts::CreateExtensionSystem() {
   DCHECK(browser_context_);
-  extension_system_ =
-      new extensions::ShellExtensionSystem(browser_context_.get());
-  extensions::ExtensionSystemFactory::GetInstance()->SetCustomInstance(
-      extension_system_);
-  // Must occur after setting the instance above, as it will end up calling
-  // ExtensionSystem::Get().
+  extension_system_ = static_cast<ShellExtensionSystem*>(
+      ExtensionSystem::GetForBrowserContext(browser_context_.get()));
   extension_system_->InitForRegularProfile(true);
 }
 

apps/shell/shell_browser_main_parts.h

@@ -21,6 +21,7 @@ struct MainFunctionParams;
 }
 
 namespace extensions {
+class ShellExtensionsBrowserClient;
 class ShellExtensionSystem;
 }
 
@@ -31,7 +32,6 @@ class WMTestHelper;
 namespace apps {
 
 class ShellBrowserContext;
-class ShellExtensionsBrowserClient;
 class ShellExtensionsClient;
 
 // Handles initialization of AppShell.
@@ -71,7 +71,8 @@ class ShellBrowserMainParts : public content::BrowserMainParts,
 
   scoped_ptr<ShellBrowserContext> browser_context_;
   scoped_ptr<ShellExtensionsClient> extensions_client_;
-  scoped_ptr<ShellExtensionsBrowserClient> extensions_browser_client_;
+  scoped_ptr<extensions::ShellExtensionsBrowserClient>
+      extensions_browser_client_;
 
   // Enable a minimal set of views::corewm to be initialized.
   scoped_ptr<wm::WMTestHelper> wm_test_helper_;

apps/shell/shell_extensions_browser_client.cc

@@ -5,26 +5,28 @@
 #include "apps/shell/shell_extensions_browser_client.h"
 
 #include "apps/shell/shell_app_sorting.h"
+#include "apps/shell/shell_extension_system.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/pref_service_factory.h"
 #include "base/prefs/testing_pref_store.h"
 #include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_prefs_factory.h"
 #include "components/user_prefs/pref_registry_syncable.h"
 #include "components/user_prefs/user_prefs.h"
 #include "extensions/browser/app_sorting.h"
 
 using content::BrowserContext;
 
+namespace extensions {
 namespace {
 
 // See chrome::RegisterProfilePrefs() in chrome/browser/prefs/browser_prefs.cc
 void RegisterPrefs(user_prefs::PrefRegistrySyncable* registry) {
-  extensions::ExtensionPrefs::RegisterProfilePrefs(registry);
+  ExtensionPrefs::RegisterProfilePrefs(registry);
 }
 
 }  // namespace
 
-namespace apps {
 
 ShellExtensionsBrowserClient::ShellExtensionsBrowserClient(
     BrowserContext* context)
@@ -101,9 +103,8 @@ bool ShellExtensionsBrowserClient::DidVersionUpdate(BrowserContext* context) {
   return false;
 }
 
-scoped_ptr<extensions::AppSorting>
-ShellExtensionsBrowserClient::CreateAppSorting() {
-  return scoped_ptr<extensions::AppSorting>(new ShellAppSorting).Pass();
+scoped_ptr<AppSorting> ShellExtensionsBrowserClient::CreateAppSorting() {
+  return scoped_ptr<AppSorting>(new apps::ShellAppSorting).Pass();
 }
 
 bool ShellExtensionsBrowserClient::IsRunningInForcedAppMode() {
@@ -118,4 +119,16 @@ ShellExtensionsBrowserClient::GetJavaScriptDialogManager() {
   return NULL;
 }
 
-}  // namespace apps
+std::vector<BrowserContextKeyedServiceFactory*>
+ShellExtensionsBrowserClient::GetExtensionSystemDependencies() {
+  std::vector<BrowserContextKeyedServiceFactory*> depends_on;
+  depends_on.push_back(ExtensionPrefsFactory::GetInstance());
+  return depends_on;
+}
+
+ExtensionSystem* ShellExtensionsBrowserClient::CreateExtensionSystem(
+    BrowserContext* context) {
+  return new ShellExtensionSystem(context);
+}
+
+}  // namespace extensions

apps/shell/shell_extensions_browser_client.h

@@ -10,18 +10,17 @@
 
 class PrefService;
 
-namespace apps {
+namespace extensions {
 
 // An ExtensionsBrowserClient that supports a single content::BrowserContent
 // with no related incognito context.
-class ShellExtensionsBrowserClient
-    : public extensions::ExtensionsBrowserClient {
+class ShellExtensionsBrowserClient : public ExtensionsBrowserClient {
  public:
   // |context| is the single BrowserContext used for IsValidContext() below.
   explicit ShellExtensionsBrowserClient(content::BrowserContext* context);
   virtual ~ShellExtensionsBrowserClient();
 
-  // extensions::ExtensionsBrowserClient overrides:
+  // ExtensionsBrowserClient overrides:
   virtual bool IsShuttingDown() OVERRIDE;
   virtual bool AreExtensionsDisabled(const CommandLine& command_line,
                                      content::BrowserContext* context) OVERRIDE;
@@ -41,10 +40,14 @@ class ShellExtensionsBrowserClient
   virtual bool IsBackgroundPageAllowed(content::BrowserContext* context)
       const OVERRIDE;
   virtual bool DidVersionUpdate(content::BrowserContext* context) OVERRIDE;
-  virtual scoped_ptr<extensions::AppSorting> CreateAppSorting() OVERRIDE;
+  virtual scoped_ptr<AppSorting> CreateAppSorting() OVERRIDE;
   virtual bool IsRunningInForcedAppMode() OVERRIDE;
   virtual content::JavaScriptDialogManager* GetJavaScriptDialogManager()
       OVERRIDE;
+  virtual std::vector<BrowserContextKeyedServiceFactory*>
+      GetExtensionSystemDependencies() OVERRIDE;
+  virtual ExtensionSystem* CreateExtensionSystem(
+      content::BrowserContext* context) OVERRIDE;
 
  private:
   // The single BrowserContext for app_shell. Not owned.
@@ -56,6 +59,6 @@ class ShellExtensionsBrowserClient
   DISALLOW_COPY_AND_ASSIGN(ShellExtensionsBrowserClient);
 };
 
-}  // namespace apps
+}  // namespace extensions
 
 #endif  // APPS_SHELL_SHELL_EXTENSIONS_BROWSER_CLIENT_H_

chrome/browser/chromeos/drive/drive_integration_service.cc

@@ -540,6 +540,18 @@ void DriveIntegrationService::AvoidDriveAsDownloadDirecotryPreference() {
 
 //===================== DriveIntegrationServiceFactory =======================
 
+DriveIntegrationServiceFactory::FactoryCallback*
+    DriveIntegrationServiceFactory::factory_for_test_ = NULL;
+
+DriveIntegrationServiceFactory::ScopedFactoryForTest::ScopedFactoryForTest(
+    FactoryCallback* factory_for_test) {
+  factory_for_test_ = factory_for_test;
+}
+
+DriveIntegrationServiceFactory::ScopedFactoryForTest::~ScopedFactoryForTest() {
+  factory_for_test_ = NULL;
+}
+
 // static
 DriveIntegrationService* DriveIntegrationServiceFactory::GetForProfile(
     Profile* profile) {
@@ -573,12 +585,6 @@ DriveIntegrationServiceFactory* DriveIntegrationServiceFactory::GetInstance() {
   return Singleton<DriveIntegrationServiceFactory>::get();
 }
 
-// static
-void DriveIntegrationServiceFactory::SetFactoryForTest(
-    const FactoryCallback& factory_for_test) {
-  GetInstance()->factory_for_test_ = factory_for_test;
-}
-
 DriveIntegrationServiceFactory::DriveIntegrationServiceFactory()
     : BrowserContextKeyedServiceFactory(
         "DriveIntegrationService",
@@ -597,7 +603,7 @@ DriveIntegrationServiceFactory::BuildServiceInstanceFor(
   Profile* profile = Profile::FromBrowserContext(context);
 
   DriveIntegrationService* service = NULL;
-  if (factory_for_test_.is_null()) {
+  if (!factory_for_test_) {
     DriveIntegrationService::PreferenceWatcher* preference_watcher = NULL;
     if (chromeos::IsProfileAssociatedWithGaiaAccount(profile)) {
       // Drive File System can be enabled.
@@ -608,7 +614,7 @@ DriveIntegrationServiceFactory::BuildServiceInstanceFor(
     service = new DriveIntegrationService(profile, preference_watcher,
                                           NULL, base::FilePath(), NULL);
   } else {
-    service = factory_for_test_.Run(profile);
+    service = factory_for_test_->Run(profile);
   }
 
   return service;

chrome/browser/chromeos/drive/drive_integration_service.h

@@ -188,6 +188,14 @@ class DriveIntegrationServiceFactory
   typedef base::Callback<DriveIntegrationService*(Profile* profile)>
       FactoryCallback;
 
+  // Sets and resets a factory function for tests. See below for why we can't
+  // use BrowserContextKeyedServiceFactory::SetTestingFactory().
+  class ScopedFactoryForTest {
+   public:
+    explicit ScopedFactoryForTest(FactoryCallback* factory_for_test);
+    ~ScopedFactoryForTest();
+  };
+
   // Returns the DriveIntegrationService for |profile|, creating it if it is
   // not yet created.
   static DriveIntegrationService* GetForProfile(Profile* profile);
@@ -207,9 +215,6 @@ class DriveIntegrationServiceFactory
   // Returns the DriveIntegrationServiceFactory instance.
   static DriveIntegrationServiceFactory* GetInstance();
 
-  // Sets a factory function for tests.
-  static void SetFactoryForTest(const FactoryCallback& factory_for_test);
-
  private:
   friend struct DefaultSingletonTraits<DriveIntegrationServiceFactory>;
 
@@ -220,7 +225,12 @@ class DriveIntegrationServiceFactory
   virtual BrowserContextKeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const OVERRIDE;
 
-  FactoryCallback factory_for_test_;
+  // This is static so it can be set without instantiating the factory. This
+  // allows factory creation to be delayed until it normally happens (on profile
+  // creation) rather than when tests are set up. DriveIntegrationServiceFactory
+  // transitively depends on ExtensionSystemFactory which crashes if created too
+  // soon (i.e. before the BrowserProcess exists).
+  static FactoryCallback* factory_for_test_;
 };
 
 }  // namespace drive

chrome/browser/chromeos/file_manager/external_filesystem_apitest.cc

@@ -43,6 +43,7 @@
 // - Doing searches on drive file system from file browser extension (using
 //   fileBrowserPrivate API).
 
+using drive::DriveIntegrationServiceFactory;
 using extensions::Extension;
 
 namespace file_manager {
@@ -298,10 +299,13 @@ class DriveFileSystemExtensionApiTest : public FileSystemExtensionApiTestBase {
     // initialized by EventRouter.
     ASSERT_TRUE(test_cache_root_.CreateUniqueTempDir());
 
-    drive::DriveIntegrationServiceFactory::SetFactoryForTest(
-        base::Bind(
+    // This callback will get called during Profile creation.
+    create_drive_integration_service_ = base::Bind(
         &DriveFileSystemExtensionApiTest::CreateDriveIntegrationService,
-            base::Unretained(this)));
+        base::Unretained(this));
+    service_factory_for_test_.reset(
+        new DriveIntegrationServiceFactory::ScopedFactoryForTest(
+            &create_drive_integration_service_));
   }
 
   // FileSystemExtensionApiTestBase OVERRIDE.
@@ -326,6 +330,10 @@ class DriveFileSystemExtensionApiTest : public FileSystemExtensionApiTestBase {
 
   base::ScopedTempDir test_cache_root_;
   drive::FakeDriveService* fake_drive_service_;
+  DriveIntegrationServiceFactory::FactoryCallback
+      create_drive_integration_service_;
+  scoped_ptr<DriveIntegrationServiceFactory::ScopedFactoryForTest>
+      service_factory_for_test_;
 };
 
 //

chrome/browser/chromeos/file_manager/file_manager_browsertest.cc

@@ -42,6 +42,8 @@
 #include "net/test/embedded_test_server/embedded_test_server.h"
 #include "webkit/browser/fileapi/external_mount_points.h"
 
+using drive::DriveIntegrationServiceFactory;
+
 namespace file_manager {
 namespace {
 
@@ -270,14 +272,17 @@ class DriveTestVolume {
   }
 
   // Sends request to add this volume to the file system as Google drive.
-  // This method must be calld at SetUp method of FileManagerBrowserTestBase.
+  // This method must be called at SetUp method of FileManagerBrowserTestBase.
   // Returns true on success.
   bool SetUp() {
     if (!test_cache_root_.CreateUniqueTempDir())
       return false;
-    drive::DriveIntegrationServiceFactory::SetFactoryForTest(
+    create_drive_integration_service_ =
         base::Bind(&DriveTestVolume::CreateDriveIntegrationService,
-                   base::Unretained(this)));
+                   base::Unretained(this));
+    service_factory_for_test_.reset(
+        new DriveIntegrationServiceFactory::ScopedFactoryForTest(
+            &create_drive_integration_service_));
     return true;
   }
 
@@ -414,6 +419,10 @@ class DriveTestVolume {
   base::ScopedTempDir test_cache_root_;
   drive::FakeDriveService* fake_drive_service_;
   drive::DriveIntegrationService* integration_service_;
+  DriveIntegrationServiceFactory::FactoryCallback
+      create_drive_integration_service_;
+  scoped_ptr<DriveIntegrationServiceFactory::ScopedFactoryForTest>
+      service_factory_for_test_;
 };
 
 // Listener to obtain the test relative messages synchronously.

chrome/browser/extensions/api/sync_file_system/sync_file_system_apitest.cc

@@ -37,13 +37,10 @@ namespace {
 
 class SyncFileSystemApiTest : public ExtensionApiTest {
  public:
-  SyncFileSystemApiTest() {}
+  SyncFileSystemApiTest()
+      : mock_remote_service_(NULL), real_default_quota_(0) {}
 
   virtual void SetUpInProcessBrowserTestFixture() OVERRIDE {
-    mock_remote_service_ = new ::testing::NiceMock<MockRemoteFileSyncService>;
-    SyncFileSystemServiceFactory::GetInstance()->set_mock_remote_file_service(
-        scoped_ptr<RemoteFileSyncService>(mock_remote_service_));
-
     ExtensionApiTest::SetUpInProcessBrowserTestFixture();
     // TODO(calvinlo): Update test code after default quota is made const
     // (http://crbug.com/155488).
@@ -56,6 +53,16 @@ class SyncFileSystemApiTest : public ExtensionApiTest {
     ExtensionApiTest::TearDownInProcessBrowserTestFixture();
   }
 
+  virtual void SetUpOnMainThread() OVERRIDE {
+    // Must happen after the browser process is created because instantiating
+    // the factory will instantiate ExtensionSystemFactory which depends on
+    // ExtensionsBrowserClient setup in BrowserProcessImpl.
+    mock_remote_service_ = new ::testing::NiceMock<MockRemoteFileSyncService>;
+    SyncFileSystemServiceFactory::GetInstance()->set_mock_remote_file_service(
+        scoped_ptr<RemoteFileSyncService>(mock_remote_service_));
+    ExtensionApiTest::SetUpOnMainThread();
+  }
+
   ::testing::NiceMock<MockRemoteFileSyncService>* mock_remote_service() {
     return mock_remote_service_;
   }

chrome/browser/extensions/chrome_extensions_browser_client.cc

@@ -10,6 +10,8 @@
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/chrome_app_sorting.h"
 #include "chrome/browser/extensions/extension_prefs.h"
+#include "chrome/browser/extensions/extension_system.h"
+#include "chrome/browser/extensions/extension_system_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/app_modal_dialogs/javascript_dialog_manager.h"
@@ -154,4 +156,16 @@ ChromeExtensionsBrowserClient::GetJavaScriptDialogManager() {
   return GetJavaScriptDialogManagerInstance();
 }
 
+std::vector<BrowserContextKeyedServiceFactory*>
+ChromeExtensionsBrowserClient::GetExtensionSystemDependencies() {
+  std::vector<BrowserContextKeyedServiceFactory*> dependencies;
+  dependencies.push_back(ExtensionSystemSharedFactory::GetInstance());
+  return dependencies;
+}
+
+ExtensionSystem* ChromeExtensionsBrowserClient::CreateExtensionSystem(
+    content::BrowserContext* context) {
+  return new ExtensionSystemImpl(static_cast<Profile*>(context));
+}
+
 }  // namespace extensions

chrome/browser/extensions/chrome_extensions_browser_client.h

@@ -55,6 +55,10 @@ class ChromeExtensionsBrowserClient : public ExtensionsBrowserClient {
   virtual bool IsRunningInForcedAppMode() OVERRIDE;
   virtual content::JavaScriptDialogManager* GetJavaScriptDialogManager()
       OVERRIDE;
+  virtual std::vector<BrowserContextKeyedServiceFactory*>
+      GetExtensionSystemDependencies() OVERRIDE;
+  virtual ExtensionSystem* CreateExtensionSystem(
+      content::BrowserContext* context) OVERRIDE;
 
  private:
   friend struct base::DefaultLazyInstanceTraits<ChromeExtensionsBrowserClient>;

chrome/browser/extensions/extension_system_factory.cc

@@ -52,8 +52,7 @@ ExtensionSystemSharedFactory::BuildServiceInstanceFor(
 content::BrowserContext* ExtensionSystemSharedFactory::GetBrowserContextToUse(
     content::BrowserContext* context) const {
   // Redirected in incognito.
-  return extensions::ExtensionsBrowserClient::Get()->
-      GetOriginalContext(context);
+  return ExtensionsBrowserClient::Get()->GetOriginalContext(context);
 }
 
 // ExtensionSystemFactory
@@ -72,24 +71,21 @@ ExtensionSystemFactory* ExtensionSystemFactory::GetInstance() {
 ExtensionSystemFactory::ExtensionSystemFactory()
     : BrowserContextKeyedServiceFactory(
         "ExtensionSystem",
-        BrowserContextDependencyManager::GetInstance()),
-      custom_instance_(NULL) {
-  DependsOn(ExtensionSystemSharedFactory::GetInstance());
+        BrowserContextDependencyManager::GetInstance()) {
+  DCHECK(ExtensionsBrowserClient::Get())
+      << "ExtensionSystemFactory must be initialized after BrowserProcess";
+  std::vector<BrowserContextKeyedServiceFactory*> dependencies =
+      ExtensionsBrowserClient::Get()->GetExtensionSystemDependencies();
+  for (size_t i = 0; i < dependencies.size(); ++i)
+    DependsOn(dependencies[i]);
 }
 
 ExtensionSystemFactory::~ExtensionSystemFactory() {
 }
 
-void ExtensionSystemFactory::SetCustomInstance(
-    ExtensionSystem* extension_system) {
-  custom_instance_ = extension_system;
-}
-
 BrowserContextKeyedService* ExtensionSystemFactory::BuildServiceInstanceFor(
-    content::BrowserContext* profile) const {
-  if (custom_instance_)
-    return custom_instance_;
-  return new ExtensionSystemImpl(static_cast<Profile*>(profile));
+    content::BrowserContext* context) const {
+  return ExtensionsBrowserClient::Get()->CreateExtensionSystem(context);
 }
 
 content::BrowserContext* ExtensionSystemFactory::GetBrowserContextToUse(

chrome/browser/extensions/extension_system_factory.h

@@ -44,10 +44,6 @@ class ExtensionSystemFactory : public BrowserContextKeyedServiceFactory {
 
   static ExtensionSystemFactory* GetInstance();
 
-  // Provides a custom ExtensionSystem to use instead of building a new
-  // ExtensionSystemImpl. The BrowserContextKeyedService system takes ownership.
-  void SetCustomInstance(ExtensionSystem* extension_system);
-
  private:
   friend struct DefaultSingletonTraits<ExtensionSystemFactory>;
 
@@ -59,8 +55,6 @@ class ExtensionSystemFactory : public BrowserContextKeyedServiceFactory {
   virtual content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const OVERRIDE;
   virtual bool ServiceIsCreatedWithBrowserContext() const OVERRIDE;
-
-  ExtensionSystem* custom_instance_;  // Not owned.
 };
 
 }  // namespace extensions

extensions/browser/extensions_browser_client.h

@@ -5,8 +5,11 @@
 #ifndef EXTENSIONS_BROWSER_EXTENSIONS_BROWSER_CLIENT_H_
 #define EXTENSIONS_BROWSER_EXTENSIONS_BROWSER_CLIENT_H_
 
+#include <vector>
+
 #include "base/memory/scoped_ptr.h"
 
+class BrowserContextKeyedServiceFactory;
 class CommandLine;
 class PrefService;
 
@@ -18,6 +21,7 @@ class JavaScriptDialogManager;
 namespace extensions {
 
 class AppSorting;
+class ExtensionSystem;
 
 // Interface to allow the extensions module to make browser-process-specific
 // queries of the embedder. Should be Set() once in the browser process.
@@ -87,6 +91,14 @@ class ExtensionsBrowserClient {
   // does not support JavaScript dialogs.
   virtual content::JavaScriptDialogManager* GetJavaScriptDialogManager() = 0;
 
+  // Returns the dependencies of ExtensionSystem. May return an empty list.
+  virtual std::vector<BrowserContextKeyedServiceFactory*>
+      GetExtensionSystemDependencies() = 0;
+
+  // Creates a new ExtensionSystem for |context|.
+  virtual ExtensionSystem* CreateExtensionSystem(
+      content::BrowserContext* context) = 0;
+
   // Returns the single instance of |this|.
   static ExtensionsBrowserClient* Get();