[Sync] Convert DTCs to be not RefCounted and NonThreadSafe.

chrome/browser/sync/glue/extension_data_type_controller.h

Index: chrome/browser/sync/glue/extension_data_type_controller.h
diff --git a/chrome/browser/sync/glue/extension_data_type_controller.h b/chrome/browser/sync/glue/extension_data_type_controller.h
index b057d0752190939a41c96dae30c544d2c00825d3..dd48b8f61164cb068e484e67133a90caece4ae55 100644
--- a/chrome/browser/sync/glue/extension_data_type_controller.h
+++ b/chrome/browser/sync/glue/extension_data_type_controller.h
@@ -20,15 +20,15 @@ namespace browser_sync {
 // both actually handle the APP datatypes as well.
 class ExtensionDataTypeController : public sync_driver::UIDataTypeController {
  public:
+  // |dump_stack| is called when an unrecoverable error occurs.

[skym, 2016/09/02 22:45:28]

again, not always

[maxbogue, 2016/09/03 00:14:50]

Acknowledged.

   ExtensionDataTypeController(
       syncer::ModelType type,  // Either EXTENSIONS or APPS.
-      const base::Closure& error_callback,
+      const base::Closure& dump_stack,
       sync_driver::SyncClient* sync_client,
       Profile* profile);
-
- private:
   ~ExtensionDataTypeController() override;
 
+ private:
   // DataTypeController implementations.
   bool StartModels() override;