aura-mus: Implement stacking in DesktopWindowTreeHostMus.

ui/views/mus/desktop_window_tree_host_mus_unittest.cc

Index: ui/views/mus/desktop_window_tree_host_mus_unittest.cc
diff --git a/ui/views/mus/desktop_window_tree_host_mus_unittest.cc b/ui/views/mus/desktop_window_tree_host_mus_unittest.cc
index 74ed9522f0f158176d4889a892fd37df63ca7669..0b63897e804bde974d3582b3fbe5a25ccc8e5e04 100644
--- a/ui/views/mus/desktop_window_tree_host_mus_unittest.cc
+++ b/ui/views/mus/desktop_window_tree_host_mus_unittest.cc
@@ -9,7 +9,10 @@
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "ui/aura/client/cursor_client.h"
+#include "ui/aura/mus/in_flight_change.h"
 #include "ui/aura/window.h"
+#include "ui/views/mus/mus_client_test_observer.h"
+#include "ui/views/mus/test_utils.h"
 #include "ui/views/test/views_test_base.h"
 #include "ui/views/widget/widget.h"
 #include "ui/views/widget/widget_delegate.h"
@@ -102,6 +105,46 @@ class ExpectsNullCursorClientDuringTearDown : public aura::WindowObserver {
   DISALLOW_COPY_AND_ASSIGN(ExpectsNullCursorClientDuringTearDown);
 };
 
+class WaitForChangeCompletor : public test::MusClientTestObserver {
+ public:
+  WaitForChangeCompletor(aura::ChangeType type,
+                         bool success)
+      : type_(type),
+        success_(success),
+        received_(false) {
+    test::MusClientTestApi::SetChangeTestObserver(this);
+  }
+
+  ~WaitForChangeCompletor() override {
+    test::MusClientTestApi::SetChangeTestObserver(nullptr);
+  }
+
+  void Wait() {
+    if (!received_) {
+      quit_closure_ = run_loop_.QuitClosure();
+      run_loop_.Run();
+    }
+  }
+
+ private:
+  // test::MusClientTestObserver:
+  void OnChangeCompleted(aura::ChangeType type, bool success) override {
+    if (type == type_ && success == success_) {
+      received_ = true;
+      if (quit_closure_)
+        quit_closure_.Run();
+    }
+  }
+
+  base::RunLoop run_loop_;
+  aura::ChangeType type_;
+  bool success_;
+  bool received_;
+  base::Closure quit_closure_;
+
+  DISALLOW_COPY_AND_ASSIGN(WaitForChangeCompletor);
+};
+
 TEST_F(DesktopWindowTreeHostMusTest, Visibility) {
   std::unique_ptr<Widget> widget(CreateWidget(nullptr));
   EXPECT_FALSE(widget->IsVisible());
@@ -147,4 +190,32 @@ TEST_F(DesktopWindowTreeHostMusTest, CursorClientDuringTearDown) {
   widget.reset();
 }
 
+TEST_F(DesktopWindowTreeHostMusTest, StackAtTop) {
+  std::unique_ptr<Widget> widget1(CreateWidget(nullptr));
+  widget1->Show();
+
+  std::unique_ptr<Widget> widget2(CreateWidget(nullptr));
+  widget2->Show();
+
+  WaitForChangeCompletor waiter(aura::ChangeType::REORDER, true);
+  widget1->StackAtTop();
+  waiter.Wait();
+
+  // Other than the signal that our StackAtTop() succeeded, we don't have any
+  // pieces of public data that we can check. If we actually stopped waiting,
+  // count that as success.
+}
+
+TEST_F(DesktopWindowTreeHostMusTest, StackAtTopAlreadyOnTop) {
+  std::unique_ptr<Widget> widget1(CreateWidget(nullptr));
+  widget1->Show();
+
+  std::unique_ptr<Widget> widget2(CreateWidget(nullptr));
+  widget2->Show();
+
+  WaitForChangeCompletor waiter(aura::ChangeType::REORDER, true);
+  widget2->StackAtTop();
+  waiter.Wait();
+}
+
 }  // namespace views