Enable sync for the settings from the Extension Settings API.

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/compiler_specific.h"
 #include "base/file_path.h"
+#include "base/memory/linked_ptr.h"
 #include "base/memory/ref_counted.h"
-#include "chrome/browser/extensions/extension_settings_storage.h"
+#include "base/task.h"
+#include "chrome/browser/extensions/syncable_extension_settings_storage.h"
+#include "chrome/browser/sync/api/syncable_service.h"
 
-// Manages ExtensionSettingsStorage objects for extensions.
-class ExtensionSettings : public base::RefCountedThreadSafe<ExtensionSettings> {
+// Manages ExtensionSettingsStorage objects for extensions, including routing
+// changes from sync to them.
+// Lives entirely on the FILE thread.
+class 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);
 
+  virtual ~ExtensionSettings();
+
   // Gets a weak reference to the storage area for a given extension.
   // Must be run on the FILE thread.
   //
   // 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.
-  ExtensionSettingsStorage* GetStorage(const std::string& extension_id);
+  ExtensionSettingsStorage* GetStorage(
+      const std::string& extension_id) const;
 
   // Gets a weak reference to the 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.
   ExtensionSettingsStorage* GetStorageForTesting(
       ExtensionSettingsStorage::Type type,
       bool cached,
-      const std::string& extension_id);
+      const std::string& extension_id) const;
+
+  // 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>;
-  virtual ~ExtensionSettings();
+  // Gets a weak reference to the storage area for a given extension,
+  // initializing sync with some initial data if sync enabled.
+  //
+  // 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.
+  SyncableExtensionSettingsStorage* GetOrCreateStorageWithSyncData(
+      const std::string& extension_id, const DictionaryValue& sync_data) const;
+
+  // If a storage area exists in the cache, returns the cached storage area.
+  // Otherwise tries to create one using CreateAndInitStorage.
+  SyncableExtensionSettingsStorage* GetOrCreateAndInitStorage(
+      ExtensionSettingsStorage::Type type,
+      bool cached,
+      const std::string& extension_id,
+      const DictionaryValue& initial_sync_data) const;
 
   // Creates a storage area of a given type, optionally wrapped in a cache.
-  // Returns NULL if creation fails.
-  ExtensionSettingsStorage* CreateStorage(
+  // Returns NULL if creation fails.  Otherwise, adds the new storage area to
+  // the cache and initializes sync if sync is enabled.
+  SyncableExtensionSettingsStorage* CreateAndInitStorage(
+      ExtensionSettingsStorage::Type type,
+      bool cached,
       const std::string& extension_id,
-      ExtensionSettingsStorage::Type type,
-      bool cached);
+      const DictionaryValue& initial_sync_data) const;
+
+  // Gets all extension IDs known to extension settings.  This may not be all
+  // installed extensions.
+  std::set<std::string> GetKnownExtensionIDs() const;
 
   // 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_;
+  typedef std::map<std::string, linked_ptr<SyncableExtensionSettingsStorage> >
+      StorageObjMap;
+  mutable StorageObjMap storage_objs_;
+
+  // Current sync processor, if any.
+  SyncChangeProcessor* sync_processor_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionSettings);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SETTINGS_H_