aura-mus: Implement stacking in DesktopWindowTreeHostMus.

ui/aura/test/mus/change_completion_waiter.cc

Index: ui/aura/test/mus/change_completion_waiter.cc
diff --git a/ui/aura/test/mus/change_completion_waiter.cc b/ui/aura/test/mus/change_completion_waiter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..db1e31ce65cc7bd4d25d4c62780b32b2cc82b483
--- /dev/null
+++ b/ui/aura/test/mus/change_completion_waiter.cc
@@ -0,0 +1,56 @@
+// Copyright 2017 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 "ui/aura/test/mus/change_completion_waiter.h"
+
+#include "base/callback.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/aura/mus/in_flight_change.h"
+#include "ui/aura/mus/window_tree_client.h"
+
+namespace aura {
+namespace test {
+
+ChangeCompletionWaiter::ChangeCompletionWaiter(WindowTreeClient* client,
+                                               ChangeType type,
+                                               bool success)
+    : state_(WaitState::NOT_STARTED),
+      client_(client),
+      type_(type),
+      success_(success) {
+  client->AddTestObserver(this);
+}
+
+ChangeCompletionWaiter::~ChangeCompletionWaiter() {
+  client_->RemoveTestObserver(this);
+}
+
+void ChangeCompletionWaiter::Wait() {
+  if (state_ != WaitState::RECEIVED) {
+    quit_closure_ = run_loop_.QuitClosure();
+    run_loop_.Run();
+  }
+}
+
+void ChangeCompletionWaiter::OnChangeStarted(uint32_t change_id,
+                                             aura::ChangeType type) {
+  if (state_ == WaitState::NOT_STARTED && type == type_) {
+    state_ = WaitState::WAITING;
+    change_id_ = change_id;
+  }
+}
+
+void ChangeCompletionWaiter::OnChangeCompleted(uint32_t change_id,
+                                               aura::ChangeType type,
+                                               bool success) {
+  if (state_ == WaitState::WAITING && change_id_ == change_id) {
+    EXPECT_EQ(success_, success);
+    state_ = WaitState::RECEIVED;
+    if (quit_closure_)
+      quit_closure_.Run();
+  }
+}
+
+}  // namespace test
+}  // namespace aura