Add a Restore() method to ValueStore and make StorageAPI use it

chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h

Index: chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h
diff --git a/chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h b/chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h
index 64909ac83f786fd205613b92c3ff9b31d4f8c946..a29be336e354b086f4b82da047726596716ac523 100644
--- a/chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h
+++ b/chrome/browser/extensions/api/storage/sync_or_local_value_store_cache.h
@@ -12,11 +12,16 @@
 #include "chrome/browser/extensions/api/storage/settings_observer.h"
 #include "chrome/browser/extensions/api/storage/settings_storage_quota_enforcer.h"
 #include "chrome/browser/extensions/api/storage/value_store_cache.h"
+#include "sync/api/syncable_service.h"
 
 namespace base {
 class FilePath;
 }
 
+namespace syncer {
+class SyncableService;
+}
+
 namespace extensions {
 
 class SettingsBackend;
@@ -35,8 +40,7 @@ class SyncOrLocalValueStoreCache : public ValueStoreCache {
       const base::FilePath& profile_path);
   virtual ~SyncOrLocalValueStoreCache();
 
-  SettingsBackend* GetAppBackend() const;
-  SettingsBackend* GetExtensionBackend() const;
+  syncer::SyncableService* GetSyncableService(syncer::ModelType type) const;
 
   // ValueStoreCache implementation: