Revert of [sync] Replace FakeServer's implementation with LoopbackServer invocations.

ios/chrome/test/app/sync_test_util.mm

Index: ios/chrome/test/app/sync_test_util.mm
diff --git a/ios/chrome/test/app/sync_test_util.mm b/ios/chrome/test/app/sync_test_util.mm
index 16c5f63a31f7f2f2526bbb6b2648f8565a2c8883..cb267afa19ed240767f7f2e582d70b313278e913 100644
--- a/ios/chrome/test/app/sync_test_util.mm
+++ b/ios/chrome/test/app/sync_test_util.mm
@@ -23,6 +23,8 @@
 #include "components/sync/test/fake_server/fake_server_network_resources.h"
 #include "components/sync/test/fake_server/fake_server_verifier.h"
 #include "components/sync/test/fake_server/sessions_hierarchy.h"
+#include "components/sync/test/fake_server/tombstone_entity.h"
+#include "components/sync/test/fake_server/unique_client_entity.h"
 #include "ios/chrome/browser/autofill/personal_data_manager_factory.h"
 #include "ios/chrome/browser/browser_state/chrome_browser_state.h"
 #include "ios/chrome/browser/history/history_service_factory.h"
@@ -172,9 +174,9 @@
   autofill_profile->add_name_full(full_name);
   autofill_profile->set_guid(guid);
 
-  std::unique_ptr<syncer::LoopbackServerEntity> entity =
-      syncer::PersistentUniqueClientEntity::CreateFromEntitySpecifics(
-          guid, entity_specifics);
+  std::unique_ptr<fake_server::FakeServerEntity> entity =
+      fake_server::UniqueClientEntity::CreateForInjection(guid,
+                                                          entity_specifics);
   gSyncFakeServer->InjectEntity(std::move(entity));
 }
 
@@ -191,9 +193,8 @@
   }
   // Delete the entity if it exists.
   if (!entity_id.empty()) {
-    std::unique_ptr<syncer::LoopbackServerEntity> entity;
-    entity =
-        syncer::PersistentTombstoneEntity::CreateNew(entity_id, std::string());
+    std::unique_ptr<fake_server::FakeServerEntity> entity;
+    entity = fake_server::TombstoneEntity::Create(entity_id, std::string());
     gSyncFakeServer->InjectEntity(std::move(entity));
   }
 }
@@ -262,9 +263,8 @@
   typedUrl->add_visits(base::Time::Max().ToInternalValue());
   typedUrl->add_visit_transitions(sync_pb::SyncEnums::TYPED);
 
-  std::unique_ptr<syncer::LoopbackServerEntity> entity =
-      syncer::PersistentUniqueClientEntity::CreateFromEntitySpecifics(
-          url, entitySpecifics);
+  std::unique_ptr<fake_server::FakeServerEntity> entity =
+      fake_server::UniqueClientEntity::CreateForInjection(url, entitySpecifics);
   gSyncFakeServer->InjectEntity(std::move(entity));
 }
 
@@ -342,9 +342,8 @@
     }
   }
   if (!entity_id.empty()) {
-    std::unique_ptr<syncer::LoopbackServerEntity> entity;
-    entity =
-        syncer::PersistentTombstoneEntity::CreateNew(entity_id, std::string());
+    std::unique_ptr<fake_server::FakeServerEntity> entity;
+    entity = fake_server::TombstoneEntity::Create(entity_id, std::string());
     gSyncFakeServer->InjectEntity(std::move(entity));
   }
 }