Support creation of toplevel mus::Windows on separate displays

ash/mus/window_manager_unittest.cc

Index: ash/mus/window_manager_unittest.cc
diff --git a/ash/mus/window_manager_unittest.cc b/ash/mus/window_manager_unittest.cc
index 62a86dd139ee9f3db49fb7ca8a04f9547414e7d5..db2914641a310aff9334cb07d4f9ffdbf65fd66d 100644
--- a/ash/mus/window_manager_unittest.cc
+++ b/ash/mus/window_manager_unittest.cc
@@ -4,6 +4,7 @@
 
 #include <memory>
 
+#include "ash/mus/test/wm_test_base.h"
 #include "base/bind.h"
 #include "base/macros.h"
 #include "services/service_manager/public/cpp/service_test.h"
@@ -80,5 +81,25 @@ TEST_F(WindowManagerTest, MAYBE_OpenWindow) {
   ASSERT_TRUE(!child_client->GetRoots().empty());
 }
 
+using WindowManagerAshTest = mus::WmTestBase;

[mfomitchev, 2016/11/18 21:23:40]

WindowManagerDisplayTest?

[thanhph, 2016/11/21 14:37:53]

Thanks! I changed it WindowManagerDualDisplayTest.

+
+TEST_F(WindowManagerAshTest, isWidgetShownInCorrectDisplay) {

[mfomitchev, 2016/11/18 21:23:40]

Capitalize first letter. Widget -> Window.

[thanhph, 2016/11/21 14:37:53]

Done.

+  if (!SupportsMultipleDisplays())
+    return;
+
+  UpdateDisplay("400x400,400x400");
+  EXPECT_NE(GetPrimaryDisplay().id(), GetSecondaryDisplay().id());
+
+  ui::Window* ui_primary_window =

[mfomitchev, 2016/11/18 21:23:40]

window_primary_display, window_secondary_display.

[thanhph, 2016/11/21 14:37:53]

Done.

+      CreateFullscreenTestWindow(GetPrimaryDisplay().id());
+  ui::Window* ui_secondary_window =
+      CreateFullscreenTestWindow(GetSecondaryDisplay().id());
+
+  DCHECK(ui_primary_window);
+  DCHECK(ui_secondary_window);
+
+  EXPECT_NE(ui_primary_window->display_id(), ui_secondary_window->display_id());

[mfomitchev, 2016/11/18 21:23:40]

A better test would be to actually ensure the two display ids are the ones we
asked for, not just that they aren't equal to each other.

[thanhph, 2016/11/21 14:37:53]

Done. Thanks!

+}
+
 }  // namespace mus
 }  // namespace ash