Revert of [Sync] Stop accessing BrowserContextKeyedServiceFactory on non-UI thread.

components/sync/driver/fake_generic_change_processor.h

Index: components/sync/driver/fake_generic_change_processor.h
diff --git a/components/sync/driver/fake_generic_change_processor.h b/components/sync/driver/fake_generic_change_processor.h
index 351874052edcc0025c7fe1f09c5eb41150113c66..395d8dbc7be599bbc9032b6fe9328e4184a204b2 100644
--- a/components/sync/driver/fake_generic_change_processor.h
+++ b/components/sync/driver/fake_generic_change_processor.h
@@ -20,7 +20,7 @@
 // A fake GenericChangeProcessor that can return arbitrary values.
 class FakeGenericChangeProcessor : public GenericChangeProcessor {
  public:
-  explicit FakeGenericChangeProcessor(ModelType type);
+  FakeGenericChangeProcessor(ModelType type, SyncClient* sync_client);
   ~FakeGenericChangeProcessor() override;
 
   // Setters for GenericChangeProcessor implementation results.
@@ -53,7 +53,7 @@
       std::unique_ptr<DataTypeErrorHandler> error_handler,
       const base::WeakPtr<SyncableService>& local_service,
       const base::WeakPtr<SyncMergeResult>& merge_result,
-      SyncApiComponentFactory* driver_factory) override;
+      SyncClient* sync_client) override;
 
  private:
   std::unique_ptr<FakeGenericChangeProcessor> processor_;