Separate the syncing of extension settings and app settings into separate data

chrome/browser/extensions/extension_settings_frontend.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_EXTENSIONS_EXTENSION_SETTINGS_FRONTEND_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_FRONTEND_H_
 #pragma once
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list_threadsafe.h"
 #include "chrome/browser/extensions/extension_settings_observer.h"
 #include "chrome/browser/sync/api/syncable_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 
 class FilePath;
 class Profile;
-class ExtensionSettingsBackend;
 class ExtensionSettingsStorage;
 
 // The component of extension settings which runs on the UI thread, as opposed
 // to ExtensionSettingsBackend which lives on the FILE thread.
 class ExtensionSettingsFrontend : public content::NotificationObserver {
  public:
   explicit ExtensionSettingsFrontend(Profile* profile);
   virtual ~ExtensionSettingsFrontend();
 
-  typedef base::Callback<void(ExtensionSettingsBackend*)> BackendCallback;
+  typedef base::Callback<void(SyncableService*)> SyncableServiceCallback;
+  typedef base::Callback<void(ExtensionSettingsStorage*)> StorageCallback;
 
-  // Runs |callback| on the FILE thread with the extension settings.
-  void RunWithBackend(const BackendCallback& callback);
+  // Runs |callback| on the FILE thread with the SyncableService for
+  // |model_type|, either EXTENSION_SETTINGS or APP_SETTINGS.
+  void RunWithSyncableService(
+      syncable::ModelType model_type, const SyncableServiceCallback& callback);
 
-  // Adds an observer to settings changes.
-  void AddObserver(ExtensionSettingsObserver* observer);
+  // Runs |callback| on the FILE thread with the storage area for
+  // |extension_id|.  If there is no extension with that ID, the storage area
+  // will be NULL.
+  void RunWithStorage(
+      const std::string& extension_id, const StorageCallback& callback);
 
-  // Removes an observer to settings changes.
-  void RemoveObserver(ExtensionSettingsObserver* observer);
+  // Deletes the settings for an extension on the FILE thread.  Must be called
+  // from the UI thread.

[akalin, 2011/10/28 06:04:54]

The comment re. UI thread is correct, but it also applies to all other
functions.  Perhaps replace this with a comment above the functions like "All
public functions below must be called on the UI thread"?

[not at google - send to devlin, 2011/10/31 00:02:23]

Done.

+  void DeleteStorageSoon(const std::string& extension_id);
+
+  // Gets the thread-safe observer list.
+  scoped_refptr<ExtensionSettingsObserverList> GetObservers();
 
   // NotificationObserver implementation.
   virtual void Observe(
       int type,
       const content::NotificationSource& source,
       const content::NotificationDetails& details) OVERRIDE;
 
  private:
   // Observer which sends events to a target profile iff the profile isn't the
   // originating profile for the event.
@@ skipping 12 matching lines @@
   // If a scoped DefaultObserver exists, clears it and removes it as an
   // Observer.
   void ClearDefaultObserver(scoped_ptr<DefaultObserver>* observer);
 
   // The (original) Profile this Frontend belongs to.  Note that we don't store
   // the incognito version of the profile because it will change as it's
   // created and destroyed during the lifetime of Chrome.
   Profile* const profile_;
 
   // List of observers to settings changes.
-  scoped_refptr<ObserverListThreadSafe<ExtensionSettingsObserver> > observers_;
+  scoped_refptr<ExtensionSettingsObserverList> observers_;
 
   // The default original and incognito mode profile observers.
   scoped_ptr<DefaultObserver> original_profile_observer;
   scoped_ptr<DefaultObserver> incognito_profile_observer_;
 
   // Ref-counted container for the ExtensionSettingsBackend object.
   class Core;
   scoped_refptr<Core> core_;
 
   // For profile created/destroyed notifications.
   content::NotificationRegistrar registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSettingsFrontend);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_FRONTEND_H_