[Sync] ModelTypeWorker should delete tracker for entity deleted on the server

components/sync/engine_impl/model_type_worker_unittest.cc

Index: components/sync/engine_impl/model_type_worker_unittest.cc
diff --git a/components/sync/engine_impl/model_type_worker_unittest.cc b/components/sync/engine_impl/model_type_worker_unittest.cc
index 8cd0f84b488f801116fef918c0f72bfc31914821..cc4fd1bd2ff812e13ede75e9229d9a52bf6ddd15 100644
--- a/components/sync/engine_impl/model_type_worker_unittest.cc
+++ b/components/sync/engine_impl/model_type_worker_unittest.cc
@@ -1145,4 +1145,36 @@ TEST_F(ModelTypeWorkerTest, DisconnectProcessorFromSyncTest) {
   EXPECT_TRUE(IsProcessorDisconnected());
 }
 
+// Test that deleted entity can be recreated again.
+TEST_F(ModelTypeWorkerTest, RecreateDeletedEntity) {
+  NormalInitialize();
+
+  // Create, then delete entity.
+  CommitRequest(kTag1, kValue1);
+  ASSERT_TRUE(WillCommit());
+  DoSuccessfulCommit();
+
+  DeleteRequest(kTag1);
+  ASSERT_TRUE(WillCommit());
+  DoSuccessfulCommit();
+
+  // Verify that entity got deleted from the server.
+  {
+    const sync_pb::SyncEntity& entity =
+        server()->GetLastCommittedEntity(kHash1);
+    EXPECT_TRUE(entity.deleted());
+  }
+
+  // Create the same entity again.
+  CommitRequest(kTag1, kValue1);
+  ASSERT_TRUE(WillCommit());
+  DoSuccessfulCommit();
+  // Verify that there is a valid entity on the server.
+  {
+    const sync_pb::SyncEntity& entity =
+        server()->GetLastCommittedEntity(kHash1);
+    EXPECT_FALSE(entity.deleted());
+  }
+}
+
 }  // namespace syncer