text: // Copyright (c) 2012 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_EXTENSIONS_EXTENSION_SERVICE_H_
  #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
  
  #include <list>
  #include <map>
  #include <set>
  #include <string>
  #include <vector>
  
  #include "base/compiler_specific.h"
  #include "base/files/file_path.h"
  #include "base/gtest_prod_util.h"
  #include "base/memory/ref_counted.h"
  #include "base/memory/weak_ptr.h"
  #include "base/prefs/pref_change_registrar.h"
  #include "base/strings/string16.h"
  #include "chrome/browser/extensions/blacklist.h"
  #include "chrome/browser/extensions/extension_sync_service.h"
  #include "chrome/browser/extensions/pending_extension_manager.h"
  #include "content/public/browser/devtools_agent_host.h"
  #include "content/public/browser/notification_observer.h"
  #include "content/public/browser/notification_registrar.h"
  #include "extensions/browser/extension_function_histogram_value.h"
  #include "extensions/browser/extension_prefs.h"
  #include "extensions/browser/external_provider_interface.h"
  #include "extensions/browser/management_policy.h"
  #include "extensions/browser/process_manager.h"
  #include "extensions/common/extension.h"
  #include "extensions/common/extension_set.h"
  #include "extensions/common/manifest.h"
  #include "extensions/common/one_shot_event.h"
  
  class ExtensionErrorUI;
  class GURL;
  class Profile;
  
  namespace base {
  class CommandLine;
  class SequencedTaskRunner;
  class Version;
  }
  
  namespace extensions {
  class BrowserEventRouter;
  class ComponentLoader;
  class CrxInstaller;
  class ExtensionActionStorageManager;
  class ExtensionGarbageCollector;
  class ExtensionRegistry;
  class ExtensionSystem;
  class ExtensionToolbarModel;
  class ExtensionUpdater;
  class PendingExtensionManager;
  class RendererStartupHelper;
  class SharedModuleService;
  class UpdateObserver;
  }  // namespace extensions
  
  using extensions::ExtensionIdSet;
  
  namespace syncer {
  class SyncErrorFactory;
  }
  
  // This is an interface class to encapsulate the dependencies that
  // various classes have on ExtensionService. This allows easy mocking.
  class ExtensionServiceInterface
      : public base::SupportsWeakPtr<ExtensionServiceInterface> {
   public:
    virtual ~ExtensionServiceInterface() {}
  
    // DEPRECATED: Use ExtensionRegistry::enabled_extensions() instead.
    // ExtensionRegistry also has the disabled, terminated and blacklisted sets.
    virtual const extensions::ExtensionSet* extensions() const = 0;
  
    virtual extensions::PendingExtensionManager* pending_extension_manager() = 0;
  
    // Install an update.  Return true if the install can be started.
    // Set out_crx_installer to the installer if one was started.
    virtual bool UpdateExtension(
        const std::string& id,
        const base::FilePath& path,
        bool file_ownership_passed,
        const GURL& download_url,
        extensions::CrxInstaller** out_crx_installer) = 0;
    virtual const extensions::Extension* GetExtensionById(
        const std::string& id,
        bool include_disabled) const = 0;
    virtual const extensions::Extension* GetInstalledExtension(
        const std::string& id) const = 0;
  
    virtual const extensions::Extension* GetPendingExtensionUpdate(
        const std::string& extension_id) const = 0;
    virtual void FinishDelayedInstallation(const std::string& extension_id) = 0;
  
    virtual bool IsExtensionEnabled(const std::string& extension_id) const = 0;
  
    virtual void CheckManagementPolicy() = 0;
  
    // Safe to call multiple times in a row.
    //
    // TODO(akalin): Remove this method (and others) once we refactor
    // themes sync to not use it directly.
    virtual void CheckForUpdatesSoon() = 0;
  
    virtual void AddExtension(const extensions::Extension* extension) = 0;
    virtual void AddComponentExtension(
        const extensions::Extension* extension) = 0;
  
    virtual void UnloadExtension(
        const std::string& extension_id,
        extensions::UnloadedExtensionInfo::Reason reason) = 0;
    virtual void RemoveComponentExtension(const std::string& extension_id) = 0;
  
    virtual bool is_ready() = 0;
  
    // Returns task runner for crx installation file I/O operations.
    virtual base::SequencedTaskRunner* GetFileTaskRunner() = 0;
  };
  
  // Manages installed and running Chromium extensions. An instance is shared
  // between normal and incognito profiles.
  class ExtensionService
      : public ExtensionServiceInterface,
        public extensions::ExternalProviderInterface::VisitorInterface,
        public content::NotificationObserver,
        public extensions::Blacklist::Observer {
   public:
    // Returns the Extension of hosted or packaged apps, NULL otherwise.
    const extensions::Extension* GetInstalledApp(const GURL& url) const;
  
    // Returns whether the URL is from either a hosted or packaged app.
    bool IsInstalledApp(const GURL& url) const;
  
    // Attempts to uninstall an extension from a given ExtensionService. Returns
    // true iff the target extension exists.
    static bool UninstallExtensionHelper(ExtensionService* extensions_service,
                                         const std::string& extension_id);
  
    // Constructor stores pointers to |profile| and |extension_prefs| but
    // ownership remains at caller.
    ExtensionService(Profile* profile,
                     const base::CommandLine* command_line,
                     const base::FilePath& install_directory,
                     extensions::ExtensionPrefs* extension_prefs,
                     extensions::Blacklist* blacklist,
                     bool autoupdate_enabled,
                     bool extensions_enabled,
                     extensions::OneShotEvent* ready);
  
    virtual ~ExtensionService();
  
    // DEPRECATED: Use ExtensionRegistry::enabled_extensions() instead.
    // ExtensionRegistry also has the disabled, terminated and blacklisted sets.
    virtual const extensions::ExtensionSet* extensions() const OVERRIDE;
  
    const extensions::ExtensionSet* delayed_installs() const;
  
    // Gets the object managing the set of pending extensions.
    virtual extensions::PendingExtensionManager*
        pending_extension_manager() OVERRIDE;
  
    const base::FilePath& install_directory() const { return install_directory_; }
  
    // Getter and setter for the flag that specifies whether the extension is
    // being reloaded.
    bool IsBeingReloaded(const std::string& extension_id) const;
    void SetBeingReloaded(const std::string& extension_id, bool value);
  
    // Initialize and start all installed extensions.
    void Init();
  
    // Called when the associated Profile is going to be destroyed.
    void Shutdown();
  
    // Look up an extension by ID. Does not include terminated
    // extensions.
    virtual const extensions::Extension* GetExtensionById(
        const std::string& id, bool include_disabled) const OVERRIDE;
  
    // Looks up an extension by ID, regardless of whether it's enabled,
    // disabled, blacklisted, or terminated.
    // DEPRECATED: Replace with:
    // ExtensionRegistry::GetExtensionById(id, ExtensionRegistry::EVERYTHING).
    virtual const extensions::Extension* GetInstalledExtension(
        const std::string& id) const OVERRIDE;
  
    // Updates a currently-installed extension with the contents from
    // |extension_path|.
    // TODO(aa): This method can be removed. ExtensionUpdater could use
    // CrxInstaller directly instead.
    virtual bool UpdateExtension(
        const std::string& id,
        const base::FilePath& extension_path,
        bool file_ownership_passed,
        const GURL& download_url,
        extensions::CrxInstaller** out_crx_installer) OVERRIDE;
  
    // Reloads the specified extension, sending the onLaunched() event to it if it
    // currently has any window showing.
    void ReloadExtension(const std::string extension_id);
  
    // Uninstalls the specified extension. Callers should only call this method
    // with extensions that exist. |external_uninstall| is a magical parameter
    // that is only used to send information to ExtensionPrefs, which external
    // callers should never set to true.
    //
    // We pass the |extension_id| by value to avoid having it deleted from under
    // us incase someone calls it with Extension::id() or another string that we
    // are going to delete in this function.
    //
    // TODO(aa): Remove |external_uninstall| -- this information should be passed
    // to ExtensionPrefs some other way.
    virtual bool UninstallExtension(std::string extension_id,
                                    bool external_uninstall,
                                    base::string16* error);
  
    virtual bool IsExtensionEnabled(
        const std::string& extension_id) const OVERRIDE;
  
    // Enables the extension.  If the extension is already enabled, does
    // nothing.
    virtual void EnableExtension(const std::string& extension_id);
  
    // Disables the extension.  If the extension is already disabled, or
    // cannot be disabled, does nothing.
    virtual void DisableExtension(const std::string& extension_id,
        extensions::Extension::DisableReason disable_reason);
  
    // Disable non-default and non-managed extensions with ids not in
    // |except_ids|. Default extensions are those from the Web Store with
    // |was_installed_by_default| flag.
    void DisableUserExtensions(const std::vector<std::string>& except_ids);
  
    // Updates the |extension|'s granted permissions lists to include all
    // permissions in the |extension|'s manifest and re-enables the
    // extension.
    void GrantPermissionsAndEnableExtension(
        const extensions::Extension* extension);
  
    // Updates the |extension|'s granted permissions lists to include all
    // permissions in the |extensions|'s manifest.
    void GrantPermissions(
        const extensions::Extension* extension);
  
    // Check for updates (or potentially new extensions from external providers)
    void CheckForExternalUpdates();
  
    // Unload the specified extension.
    virtual void UnloadExtension(
        const std::string& extension_id,
        extensions::UnloadedExtensionInfo::Reason reason) OVERRIDE;
  
    // Remove the specified component extension.
    virtual void RemoveComponentExtension(const std::string& extension_id)
        OVERRIDE;
  
    // Unload all extensions. Does not send notifications.
    void UnloadAllExtensionsForTest();
  
    // Reloads all extensions. Does not notify that extensions are ready.
    void ReloadExtensionsForTest();
  
    // Called when the initial extensions load has completed.
    virtual void OnLoadedInstalledExtensions();
  
    // Adds |extension| to this ExtensionService and notifies observers that the
    // extensions have been loaded.
    virtual void AddExtension(const extensions::Extension* extension) OVERRIDE;
  
    // Check if we have preferences for the component extension and, if not or if
    // the stored version differs, install the extension (without requirements
    // checking) before calling AddExtension.
    virtual void AddComponentExtension(const extensions::Extension* extension)
        OVERRIDE;
  
    // Informs the service that an extension's files are in place for loading.
    //
    // |page_ordinal| is the location of the extension in the app launcher.
    // |has_requirement_errors| is true if requirements of the extension weren't
    // met (for example graphics capabilities).
    // |blacklist_state| will be BLACKLISTED if the extension is blacklisted.
    // |wait_for_idle| may be false to install the extension immediately.
    void OnExtensionInstalled(
        const extensions::Extension* extension,
        const syncer::StringOrdinal& page_ordinal,
        bool has_requirement_errors,
        extensions::BlacklistState blacklist_state,
        bool wait_for_idle);
  
    // Checks for delayed installation for all pending installs.
    void MaybeFinishDelayedInstallations();
  
    // Similar to FinishInstallation, but first checks if there still is an update
    // pending for the extension, and makes sure the extension is still idle.
    void MaybeFinishDelayedInstallation(const std::string& extension_id);
  
    // Finishes installation of an update for an extension with the specified id,
    // when installation of that extension was previously delayed because the
    // extension was in use.
    virtual void FinishDelayedInstallation(
       const std::string& extension_id) OVERRIDE;
  
    // Returns an update for an extension with the specified id, if installation
    // of that update was previously delayed because the extension was in use. If
    // no updates are pending for the extension returns NULL.
    virtual const extensions::Extension* GetPendingExtensionUpdate(
        const std::string& extension_id) const OVERRIDE;
  
    // Go through each extension and unload those that are not allowed to run by
    // management policy providers (ie. network admin and Google-managed
    // blacklist).
    virtual void CheckManagementPolicy() OVERRIDE;
  
    virtual void CheckForUpdatesSoon() OVERRIDE;
  
    void set_extensions_enabled(bool enabled) { extensions_enabled_ = enabled; }
    bool extensions_enabled() { return extensions_enabled_; }
  
    void set_show_extensions_prompts(bool enabled) {
      show_extensions_prompts_ = enabled;
    }
  
    bool show_extensions_prompts() {
      return show_extensions_prompts_;
    }
  
    Profile* profile();
  
    // Returns profile_ as a BrowserContext.
    content::BrowserContext* GetBrowserContext() const;
  
    void set_extension_sync_service(
        ExtensionSyncService* extension_sync_service) {
      extension_sync_service_ = extension_sync_service;
    }
  
    // Whether the extension service is ready.
    virtual bool is_ready() OVERRIDE;
  
    virtual base::SequencedTaskRunner* GetFileTaskRunner() OVERRIDE;
  
    extensions::ComponentLoader* component_loader() {
      return component_loader_.get();
    }
  
    // Note that this may return NULL if autoupdate is not turned on.
    extensions::ExtensionUpdater* updater();
  
    // Notify the frontend that there was an error loading an extension.
    // This method is public because UnpackedInstaller and InstalledLoader
    // can post to here.
    // TODO(aa): Remove this. It doesn't do enough to be worth the dependency
    // of these classes on ExtensionService.
    void ReportExtensionLoadError(const base::FilePath& extension_path,
                                  const std::string& error,
                                  bool be_noisy);
  
    // Notifies ExtensionSettingsHandler whether or not to retry installation for
    // given |extension_path|.
    void NotifyLoadRetry(bool retry, const base::FilePath& extension_path);
  
    // ExtensionHost of background page calls this method right after its render
    // view has been created.
    void DidCreateRenderViewForBackgroundPage(extensions::ExtensionHost* host);
  
    // For the extension in |version_path| with |id|, check to see if it's an
    // externally managed extension.  If so, uninstall it.
    void CheckExternalUninstall(const std::string& id);
  
    // Changes sequenced task runner for crx installation tasks to |task_runner|.
    void SetFileTaskRunnerForTesting(base::SequencedTaskRunner* task_runner);
  
    // Clear all ExternalProviders.
    void ClearProvidersForTesting();
  
    // Adds an ExternalProviderInterface for the service to use during testing.
    // Takes ownership of |test_provider|.
    void AddProviderForTesting(
        extensions::ExternalProviderInterface* test_provider);
  
    // ExternalProvider::Visitor implementation.
    virtual bool OnExternalExtensionFileFound(
        const std::string& id,
        const base::Version* version,
        const base::FilePath& path,
        extensions::Manifest::Location location,
        int creation_flags,
        bool mark_acknowledged) OVERRIDE;
  
    virtual bool OnExternalExtensionUpdateUrlFound(
        const std::string& id,
        const std::string& install_parameter,
        const GURL& update_url,
        extensions::Manifest::Location location,
        int creation_flags,
        bool mark_acknowledged) OVERRIDE;
  
    virtual void OnExternalProviderReady(
        const extensions::ExternalProviderInterface* provider) OVERRIDE;
  
    // Returns true when all the external extension providers are ready.
    bool AreAllExternalProvidersReady() const;
  
    void OnAllExternalProvidersReady();
  
    // Once all external providers are done, generates any needed alerts about
    // extensions.
    void IdentifyAlertableExtensions();
  
    // Given an ExtensionErrorUI alert, populates it with any extensions that
    // need alerting. Returns true if the alert should be displayed at all.
    //
    // This method takes the extension_error_ui argument rather than using
    // the member variable to make it easier to test the method in isolation.
    bool PopulateExtensionErrorUI(ExtensionErrorUI* extension_error_ui);
  
    // Checks if there are any new external extensions to notify the user about.
    void UpdateExternalExtensionAlert();
  
    // Given a (presumably just-installed) extension id, mark that extension as
    // acknowledged.
    void AcknowledgeExternalExtension(const std::string& id);
  
    // Returns true if this extension is an external one that has yet to be
    // marked as acknowledged.
    bool IsUnacknowledgedExternalExtension(
        const extensions::Extension* extension);
  
    // Disable extensions that are known to be disabled yet are currently enabled.
    void ReconcileKnownDisabled();
  
    // Opens the Extensions page because the user wants to get more details
    // about the alerts.
    void HandleExtensionAlertDetails();
  
    // Called when the extension alert is closed. Updates prefs and deletes
    // the active |extension_error_ui_|.
    void HandleExtensionAlertClosed();
  
    // Marks alertable extensions as acknowledged, after the user presses the
    // accept button.
    void HandleExtensionAlertAccept();
  
    // content::NotificationObserver
    virtual void Observe(int type,
                         const content::NotificationSource& source,
                         const content::NotificationDetails& details) OVERRIDE;
  
    // Postpone installations so that we don't have to worry about race
    // conditions.
    void OnGarbageCollectIsolatedStorageStart();
  
    // Restart any extension installs which were delayed for isolated storage
    // garbage collection.
    void OnGarbageCollectIsolatedStorageFinished();
  
    // Record a histogram using the PermissionMessage enum values for each
    // permission in |e|.
    // NOTE: If this is ever called with high frequency, the implementation may
    // need to be made more efficient.
    static void RecordPermissionMessagesHistogram(
        const extensions::Extension* e, const char* histogram);
  
  #if defined(UNIT_TEST)
    void TrackTerminatedExtensionForTest(const extensions::Extension* extension) {
      TrackTerminatedExtension(extension);
    }
  
    void FinishInstallationForTest(const extensions::Extension* extension) {
      FinishInstallation(extension);
    }
  #endif
  
    base::WeakPtr<ExtensionService> AsWeakPtr() { return base::AsWeakPtr(this); }
  
    extensions::ExtensionGarbageCollector* garbage_collector() {
      return garbage_collector_.get();
    }
  
    bool browser_terminating() const { return browser_terminating_; }
  
    extensions::SharedModuleService* shared_module_service() {
      return shared_module_service_.get();
    }
  
    // For testing.
    void set_browser_terminating_for_test(bool value) {
      browser_terminating_ = value;
    }
  
    // By default ExtensionService will wait with installing an updated extension
    // until the extension is idle. Tests might not like this behavior, so you can
    // disable it with this method.
    void set_install_updates_when_idle_for_test(bool value) {
      install_updates_when_idle_ = value;
    }
  
    // Set a callback to be called when all external providers are ready and their
    // extensions have been installed.
    void set_external_updates_finished_callback_for_test(
        const base::Closure& callback) {
      external_updates_finished_callback_ = callback;
    }
  
    // Adds/Removes update observers.
    void AddUpdateObserver(extensions::UpdateObserver* observer);
    void RemoveUpdateObserver(extensions::UpdateObserver* observer);
  
   private:
    // Populates greylist_.
    void LoadGreylistFromPrefs();
  
    // Signals *ready_ and sends a notification to the listeners.
    void SetReadyAndNotifyListeners();
  
    // Return true if the sync type of |extension| matches |type|.
    void OnExtensionInstallPrefChanged();
  
    // Adds the given extension to the list of terminated extensions if
    // it is not already there and unloads it.
    void TrackTerminatedExtension(const extensions::Extension* extension);
  
    // Removes the extension with the given id from the list of
    // terminated extensions if it is there.
    void UntrackTerminatedExtension(const std::string& id);
  
    // Update preferences for a new or updated extension; notify observers that
    // the extension is installed, e.g., to update event handlers on background
    // pages; and perform other extension install tasks before calling
    // AddExtension.
    void AddNewOrUpdatedExtension(const extensions::Extension* extension,
                                  extensions::Extension::State initial_state,
                                  extensions::BlacklistState blacklist_state,
                                  const syncer::StringOrdinal& page_ordinal,
                                  const std::string& install_parameter);
  
    // Handles sending notification that |extension| was loaded.
    void NotifyExtensionLoaded(const extensions::Extension* extension);
  
    // Handles sending notification that |extension| was unloaded.
    void NotifyExtensionUnloaded(
        const extensions::Extension* extension,
        extensions::UnloadedExtensionInfo::Reason reason);
  
    // Common helper to finish installing the given extension.
    void FinishInstallation(const extensions::Extension* extension);
  
    // Updates the |extension|'s active permission set to include only permissions
    // currently requested by the extension and all the permissions required by
    // the extension.
    void UpdateActivePermissions(const extensions::Extension* extension);
  
    // Disables the extension if the privilege level has increased
    // (e.g., due to an upgrade).
    void CheckPermissionsIncrease(const extensions::Extension* extension,
                                  bool is_extension_installed);
  
    // Helper that updates the active extension list used for crash reporting.
    void UpdateActiveExtensionsInCrashReporter();
  
    // Helper to determine whether we should initially enable an installed
    // (or upgraded) extension.
    bool ShouldEnableOnInstall(const extensions::Extension* extension);
  
    // Helper to determine if updating an extensions should proceed immediately,
    // or if we should delay the update until further notice.
    bool ShouldDelayExtensionUpdate(const std::string& extension_id,
                                    bool wait_for_idle) const;
  
    // extensions::Blacklist::Observer implementation.
    virtual void OnBlacklistUpdated() OVERRIDE;
  
    // Manages the blacklisted extensions, intended as callback from
    // Blacklist::GetBlacklistedIDs.
    void ManageBlacklist(
        const extensions::Blacklist::BlacklistStateMap& blacklisted_ids);
  
    // Add extensions in |blocked| to blacklisted_extensions, remove extensions
    // that are neither in |blocked|, nor in |unchanged|.
    void UpdateBlockedExtensions(const ExtensionIdSet& blocked,
                                 const ExtensionIdSet& unchanged);
  
    void UpdateGreylistedExtensions(
        const ExtensionIdSet& greylist,
        const ExtensionIdSet& unchanged,
        const extensions::Blacklist::BlacklistStateMap& state_map);
  
    // Used only by test code.
    void UnloadAllExtensionsInternal();
  
    // The normal profile associated with this ExtensionService.
    Profile* profile_;
  
    // The ExtensionSystem for the profile above.
    extensions::ExtensionSystem* system_;
  
    // Preferences for the owning profile.
    extensions::ExtensionPrefs* extension_prefs_;
  
    // Blacklist for the owning profile.
    extensions::Blacklist* blacklist_;
  
    // The ExtensionSyncService that is used by this ExtensionService.
    ExtensionSyncService* extension_sync_service_;
  
    // Sets of enabled/disabled/terminated/blacklisted extensions. Not owned.
    extensions::ExtensionRegistry* registry_;
  
    // Set of greylisted extensions. These extensions are disabled if they are
    // already installed in Chromium at the time when they are added to
    // the greylist. Unlike blacklisted extensions, greylisted ones are visible
    // to the user and if user re-enables such an extension, they remain enabled.
    //
    // These extensions should appear in registry_.
    extensions::ExtensionSet greylist_;
  
    // The list of extension installs delayed for various reasons.  The reason
    // for delayed install is stored in ExtensionPrefs. These are not part of
    // ExtensionRegistry because they are not yet installed.
    extensions::ExtensionSet delayed_installs_;
  
    // Hold the set of pending extensions.
    extensions::PendingExtensionManager pending_extension_manager_;
  
    // The full path to the directory where extensions are installed.
    base::FilePath install_directory_;
  
    // Whether or not extensions are enabled.
    bool extensions_enabled_;
  
    // Whether to notify users when they attempt to install an extension.
    bool show_extensions_prompts_;
  
    // Whether to delay installing of extension updates until the extension is
    // idle.
    bool install_updates_when_idle_;
  
    // Signaled when all extensions are loaded.
    extensions::OneShotEvent* const ready_;
  
    // Our extension updater, if updates are turned on.
    scoped_ptr<extensions::ExtensionUpdater> updater_;
  
    // Map unloaded extensions' ids to their paths. When a temporarily loaded
    // extension is unloaded, we lose the information about it and don't have
    // any in the extension preferences file.
    typedef std::map<std::string, base::FilePath> UnloadedExtensionPathMap;
    UnloadedExtensionPathMap unloaded_extension_paths_;
  
    // Store the ids of reloading extensions.
    std::set<std::string> reloading_extensions_;
  
    // Map of DevToolsAgentHost instances that are detached,
    // waiting for an extension to be reloaded.
    typedef std::map<std::string, scoped_refptr<content::DevToolsAgentHost> >
        OrphanedDevTools;
    OrphanedDevTools orphaned_dev_tools_;
  
    content::NotificationRegistrar registrar_;
    PrefChangeRegistrar pref_change_registrar_;
  
    // Keeps track of loading and unloading component extensions.
    scoped_ptr<extensions::ComponentLoader> component_loader_;
  
    // A collection of external extension providers.  Each provider reads
    // a source of external extension information.  Examples include the
    // windows registry and external_extensions.json.
    extensions::ProviderCollection external_extension_providers_;
  
    // Set to true by OnExternalExtensionUpdateUrlFound() when an external
    // extension URL is found, and by CheckForUpdatesSoon() when an update check
    // has to wait for the external providers.  Used in
    // OnAllExternalProvidersReady() to determine if an update check is needed to
    // install pending extensions.
    bool update_once_all_providers_are_ready_;
  
    // A callback to be called when all external providers are ready and their
    // extensions have been installed. Normally this is a null callback, but
    // is used in external provider related tests.
    base::Closure external_updates_finished_callback_;
  
    // Set when the browser is terminating. Prevents us from installing or
    // updating additional extensions and allows in-progress installations to
    // decide to abort.
    bool browser_terminating_;
  
    // Set to true to delay all new extension installations. Acts as a lock to
    // allow background processing of garbage collection of on-disk state without
    // needing to worry about race conditions caused by extension installation and
    // reinstallation.
    bool installs_delayed_for_gc_;
  
    // Set to true if this is the first time this ExtensionService has run.
    // Used for specially handling external extensions that are installed the
    // first time.
    bool is_first_run_;
  
    // A set of the extension ids currently being reloaded.  We use this to
    // avoid showing a "new install" notice for an extension reinstall.
    std::set<std::string> extensions_being_reloaded_;
  
    // A set of the extension ids currently being terminated. We use this to
    // avoid trying to unload the same extension twice.
    std::set<std::string> extensions_being_terminated_;
  
    scoped_ptr<ExtensionErrorUI> extension_error_ui_;
    // Sequenced task runner for extension related file operations.
    scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
  
  #if defined(ENABLE_EXTENSIONS)
    scoped_ptr<extensions::ExtensionActionStorageManager>
        extension_action_storage_manager_;
  #endif
    scoped_ptr<extensions::ManagementPolicy::Provider>
        shared_module_policy_provider_;
  
    // The ExtensionGarbageCollector to clean up all the garbage that leaks into
    // the extensions directory.
    scoped_ptr<extensions::ExtensionGarbageCollector> garbage_collector_;
  
    // The SharedModuleService used to check for import dependencies.
    scoped_ptr<extensions::SharedModuleService> shared_module_service_;
  
    ObserverList<extensions::UpdateObserver, true> update_observers_;
  
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             InstallAppsWithUnlimtedStorage);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             InstallAppsAndCheckStorageProtection);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest, SetUnsetBlacklistInPrefs);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             BlacklistedExtensionWillNotInstall);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             UnloadBlacklistedExtensionPolicy);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             WillNotLoadBlacklistedExtensionsFromDirectory);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             BlacklistedInPrefsFromStartup);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             GreylistedExtensionDisabled);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             GreylistDontEnableManuallyDisabled);
    FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                             GreylistUnknownDontChange);
    DISALLOW_COPY_AND_ASSIGN(ExtensionService);
  };
  
  #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
  