mus: Allow SetModal to fail gracefully

components/mus/public/cpp/tests/test_window_tree.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/mus/public/cpp/tests/test_window_tree.h"
 
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace mus {
 
@@ skipping 73 matching lines @@
                                             uint32_t window_id) {}
 
 void TestWindowTree::AddTransientWindow(uint32_t change_id,
                                         uint32_t window_id,
                                         uint32_t transient_window_id) {}
 
 void TestWindowTree::RemoveTransientWindowFromParent(
     uint32_t change_id,
     uint32_t transient_window_id) {}
 
-void TestWindowTree::SetModal(uint32_t change_id, uint32_t window_id) {}
+void TestWindowTree::SetModal(uint32_t change_id, uint32_t window_id) {
+  got_change_ = true;
+  change_id_ = change_id;
+}
 
 void TestWindowTree::ReorderWindow(uint32_t change_id,
                                    uint32_t window_id,
                                    uint32_t relative_window_id,
                                    mojom::OrderDirection direction) {}
 
 void TestWindowTree::GetWindowTree(uint32_t window_id,
                                    const GetWindowTreeCallback& callback) {}
 
 void TestWindowTree::SetCapture(uint32_t change_id, uint32_t window_id) {
@@ skipping 30 matching lines @@
 
 void TestWindowTree::OnWindowInputEventAck(uint32_t event_id, bool handled) {
   EXPECT_FALSE(acked_events_.count(event_id));
   acked_events_.insert(event_id);
 }
 
 void TestWindowTree::GetWindowManagerClient(
     mojo::AssociatedInterfaceRequest<mojom::WindowManagerClient> internal) {}
 
 }  // namespace mus