USS SyncContextProxy / data type activation refactoring

components/sync_driver/frontend_data_type_controller.h

Index: components/sync_driver/frontend_data_type_controller.h
diff --git a/components/sync_driver/frontend_data_type_controller.h b/components/sync_driver/frontend_data_type_controller.h
index 8bf4f7d1bd7e26bdb84d5b9778fdc6f742de9835..9a0bb8a6714b757debb8836ebf4861ccbb24d79c 100644
--- a/components/sync_driver/frontend_data_type_controller.h
+++ b/components/sync_driver/frontend_data_type_controller.h
@@ -80,9 +80,6 @@ class FrontendDataTypeController
   // Datatype specific creation of sync components.
   virtual void CreateSyncComponents() = 0;
 
-  // DataTypeController interface.
-  void OnModelLoaded() override;
-
   // Perform any DataType controller specific state cleanup before stopping
   // the datatype controller. The default implementation is a no-op.
   virtual void CleanUpState();
@@ -111,6 +108,11 @@ class FrontendDataTypeController
       const tracked_objects::Location& from_here,
       const std::string& message);
 
+  // If the DTC is waiting for models to load, once the models are
+  // loaded the datatype service will call this function on DTC to let
+  // us know that it is safe to start associating.
+  void OnModelLoaded();
+
   sync_driver::SyncClient* const sync_client_;
 
   State state_;