[sync] Clean up path generation for the local sync database.

components/sync/driver/sync_client.h

Index: components/sync/driver/sync_client.h
diff --git a/components/sync/driver/sync_client.h b/components/sync/driver/sync_client.h
index bf9ab4cec3fb760ff290d1161779e27b51de0cde..77d8f33eefe7bfe7b5e00679fef9bcd8a82728a0 100644
--- a/components/sync/driver/sync_client.h
+++ b/components/sync/driver/sync_client.h
@@ -67,6 +67,10 @@ class SyncClient {
   // Returns the current profile's preference service.
   virtual PrefService* GetPrefService() = 0;
 
+  // Returns the path to the folder used for storing the local sync database.
+  // It is only used when sync is running against a local backend.
+  virtual base::FilePath GetLocalSyncBackendFolder() = 0;
+
   // DataType specific service getters.
   virtual bookmarks::BookmarkModel* GetBookmarkModel() = 0;
   virtual favicon::FaviconService* GetFaviconService() = 0;