Makes display roots be destroyed by client

services/ui/ws/test_utils.cc

Index: services/ui/ws/test_utils.cc
diff --git a/services/ui/ws/test_utils.cc b/services/ui/ws/test_utils.cc
index bb59ce9aeb694c6d2541a1cb8842b17301086053..8f86857b64ef884b24b089087f6b90c6dea272ae 100644
--- a/services/ui/ws/test_utils.cc
+++ b/services/ui/ws/test_utils.cc
@@ -199,6 +199,11 @@ WindowTree* TestDisplayBinding::CreateWindowTree(ServerWindow* root) {
 
 // TestWindowManager ----------------------------------------------------------
 
+void TestWindowManager::WmDisplayRemoved(int64_t display_id) {
+  got_display_removed_ = true;
+  display_removed_id_ = display_id;
+}
+
 void TestWindowManager::WmCreateTopLevelWindow(
     uint32_t change_id,
     ClientSpecificId requesting_client_id,