[Sync] SyncEngine refactor part 2: SyncServiceBase.

components/sync/engine/sync_engine.cc

Index: components/sync/engine/sync_engine.cc
diff --git a/components/sync/engine/sync_engine.cc b/components/sync/engine/sync_engine.cc
index 53482595e3d307e3bc69797aff9ae2495b92cfa7..33beacf5a65c5111d31fc3b03f5939d3afcdb92f 100644
--- a/components/sync/engine/sync_engine.cc
+++ b/components/sync/engine/sync_engine.cc
@@ -6,7 +6,11 @@
 
 namespace syncer {
 
-SyncEngine::SyncEngine() {}
-SyncEngine::~SyncEngine() {}
+SyncEngine::InitParams::InitParams() = default;
+SyncEngine::InitParams::InitParams(InitParams&& other) = default;
+SyncEngine::InitParams::~InitParams() = default;
+
+SyncEngine::SyncEngine() = default;
+SyncEngine::~SyncEngine() = default;
 
 }  // namespace syncer