[Sync] Pass ModelTypeSet by value everywhere

sync/internal_api/public/test/fake_sync_manager.h

Index: sync/internal_api/public/test/fake_sync_manager.h
diff --git a/sync/internal_api/public/test/fake_sync_manager.h b/sync/internal_api/public/test/fake_sync_manager.h
index 939435cdeba7d2dd83497c4985a291cede8b561f..df0e3e0a7e97367b88b3c4a659e32327bb323438 100644
--- a/sync/internal_api/public/test/fake_sync_manager.h
+++ b/sync/internal_api/public/test/fake_sync_manager.h
@@ -95,7 +95,7 @@ class FakeSyncManager : public SyncManager {
       ModelTypeSet types) OVERRIDE;
   virtual bool PurgePartiallySyncedTypes() OVERRIDE;
   virtual void UpdateCredentials(const SyncCredentials& credentials) OVERRIDE;
-  virtual void UpdateEnabledTypes(const ModelTypeSet& types) OVERRIDE;
+  virtual void UpdateEnabledTypes(ModelTypeSet types) OVERRIDE;
   virtual void RegisterInvalidationHandler(
       InvalidationHandler* handler) OVERRIDE;
   virtual void UpdateRegisteredInvalidationIds(
@@ -107,7 +107,7 @@ class FakeSyncManager : public SyncManager {
       const ModelSafeRoutingInfo& routing_info) OVERRIDE;
   virtual void ConfigureSyncer(
       ConfigureReason reason,
-      const ModelTypeSet& types_to_config,
+      ModelTypeSet types_to_config,
       const ModelSafeRoutingInfo& new_routing_info,
       const base::Closure& ready_task,
       const base::Closure& retry_task) OVERRIDE;