WORK IN PROGRESS.

chrome/browser/extensions/extension_settings.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_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_H_
 #pragma once
 
 #include "base/callback.h"
+#include "base/compiler_specific.h"
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
 #include "chrome/browser/extensions/extension_settings_storage.h"
+#include "chrome/browser/extensions/extension_settings.h"
+#include "chrome/browser/extensions/extension_settings_storage.h"
+#include "chrome/browser/extensions/extension_settings_sync_data.h"
+#include "chrome/browser/extensions/syncable_extension_settings_storage.h"
+#include "chrome/browser/sync/api/syncable_service.h"
+#include "chrome/browser/sync/api/sync_data.h"
+#include "chrome/browser/sync/api/sync_change.h"
 
 // Manages ExtensionSettingsStorage objects for extensions.
-class ExtensionSettings : public base::RefCountedThreadSafe<ExtensionSettings> {
+class ExtensionSettings
+    : public base::RefCountedThreadSafe<ExtensionSettings>,
+      public SyncableService {
  public:
   // File path is the base of the extension settings directory.
   // The databases will be at base_path/extension_id.
   explicit ExtensionSettings(const FilePath& base_path);
 
   // Callback from the GetStorage() methods.
-  typedef base::Callback<void(ExtensionSettingsStorage*)> Callback;
+  typedef base::Callback<void(SyncableExtensionSettingsStorage*)> Callback;
 
   // Gets the storage area for a given extension.  Only valid for the duration
   // of the callback.
   // By default this will be of a cached LEVELDB storage, but on failure to
   // create a leveldb instance will fall back to cached NOOP storage.
   // Callbacks will happen asynchronously regardless of whether they need to go
   // to the FILE thread, but will always be called on the UI thread.
   void GetStorage(const std::string& extension_id, const Callback& callback);
 
   // Gets a storage area for a given extension with a specific type.
   // and whether it should be wrapped in a cache.
   // Use this for testing; if the given type fails to be created (e.g. if
   // leveldb creation fails) then a DCHECK will fail.
   // Callback objects will be deleted when used.
   void GetStorageForTesting(
       ExtensionSettingsStorage::Type type,
       bool cached,
       const std::string& extension_id,
       const Callback& callback);
 
+  // SyncableService implementation.
+  virtual SyncDataList GetAllSyncData(syncable::ModelType type) const OVERRIDE;
+  virtual SyncError MergeDataAndStartSyncing(
+      syncable::ModelType type,
+      const SyncDataList& initial_sync_data,
+      SyncChangeProcessor* sync_processor) OVERRIDE;
+  virtual SyncError ProcessSyncChanges(
+      const tracked_objects::Location& from_here,
+      const SyncChangeList& change_list) OVERRIDE;
+  virtual void StopSyncing(syncable::ModelType type) OVERRIDE;
+
  private:
   friend class base::RefCountedThreadSafe<ExtensionSettings>;
   ~ExtensionSettings();
 
   // Attempts to get and callback with an existing storage area.  Returns
   // whether storage existed and the callback run.
   bool GetExistingStorage(
       const std::string& extension_id, const Callback& callback);
 
   // Runs a Callback with a storage argument, then deletes the callback.
-  void RunWithStorage(Callback* callback, ExtensionSettingsStorage* storage);
+  void RunWithStorage(
+      Callback* callback, SyncableExtensionSettingsStorage* storage);
 
   // Starts the process of creation of a storage area.
   // Must be run on the UI thread.
   void StartCreationOfStorage(
       const std::string& extension_id,
       ExtensionSettingsStorage::Type type,
       ExtensionSettingsStorage::Type fallback_type,
       bool cached,
       const Callback& callback);
 
   // Creates a new storage area of a given type, with a fallback type if
   // creation fails, and optionally wrapped in a cache.
   // Must be run on the FILE thread.
   void CreateStorageOnFileThread(
       const std::string& extension_id,
       ExtensionSettingsStorage::Type type,
       ExtensionSettingsStorage::Type fallback_type,
       bool cached,
       const Callback& callback);
 
   // Creates a storage area of a given type, optionally wrapped in a cache.
+  // TODO documentation
   // Returns NULL if creation fails.
-  ExtensionSettingsStorage* CreateStorage(
+  SyncableExtensionSettingsStorage* CreateStorage(
       const std::string& extension_id,
       ExtensionSettingsStorage::Type type,
       bool cached);
 
   // End the creation of a storage area.
   // Must be run on the UI thread.
   void EndCreationOfStorage(
       const std::string& extension_id,
-      ExtensionSettingsStorage* storage,
+      SyncableExtensionSettingsStorage* storage,
       const Callback& callback);
 
+  // Start syncing some extension settings.
+  void StartSyncingStorage(
+      const std::string& extension_id,
+      SyncableExtensionSettingsStorage* storage);
+
+  // Stop syncing some extension settings.
+  void StopSyncingStorage(ExtensionSettingsStorage* storage);
+
+  // Asserts that there is no sync data for a storage area.
+  void AssertNoSyncData(
+      const std::string& extension_id,
+      SyncableExtensionSettingsStorage* storage);
+
   // The base file path to create any leveldb databases at.
   const FilePath base_path_;
 
   // A cache of ExtensionSettingsStorage objects that have already been created.
   // Ensure that there is only ever one created per extension.
-  std::map<std::string, ExtensionSettingsStorage*> storage_objs_;
+  std::map<std::string, SyncableExtensionSettingsStorage*> storage_objs_;
+
+  // Sync change processor for sync.
+  SyncChangeProcessor* sync_processor_;
+
+  // Initial settings received from sync that haven't been merged into their
+  // respective storage areas.  Populated in MergeDataAndStartSyncing and
+  // depopulated in StartSyncingStorage.
+  std::map<std::string, DictionaryValue*> unmerged_sync_data_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSettings);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_H_