Support creation of toplevel mus::Windows on separate displays

ash/mus/test/wm_test_base.cc

 // Copyright 2016 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 "ash/mus/test/wm_test_base.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "ash/mus/bridge/wm_window_mus_test_api.h"
 #include "ash/mus/root_window_controller.h"
 #include "ash/mus/test/wm_test_helper.h"
 #include "ash/mus/window_manager.h"
 #include "ash/mus/window_manager_application.h"
 #include "services/ui/public/cpp/property_type_converters.h"
 #include "services/ui/public/cpp/window_tree_client.h"
-#include "ui/display/display.h"
 
 namespace ash {
 namespace mus {
 namespace {
 
 ui::mojom::WindowType MusWindowTypeFromWmWindowType(
     ui::wm::WindowType wm_window_type) {
   switch (wm_window_type) {
     case ui::wm::WINDOW_TYPE_UNKNOWN:
       break;
@@ skipping 88 matching lines @@
 
   ui::Window* window = test_helper_->GetRootsOrderedByDisplayId()[0]
                            ->window_manager()
                            ->NewTopLevelWindow(&properties);
   window->SetVisible(true);
   // Most tests expect a minimum size of 0x0.
   WmWindowMusTestApi(WmWindowMus::Get(window)).set_use_empty_minimum_size(true);
   return window;
 }
 
-ui::Window* WmTestBase::CreateFullscreenTestWindow() {
+ui::Window* WmTestBase::CreateFullscreenTestWindow(int64_t display_id) {
   std::map<std::string, std::vector<uint8_t>> properties;
   properties[ui::mojom::WindowManager::kShowState_Property] =
       mojo::ConvertTo<std::vector<uint8_t>>(
           static_cast<int32_t>(ui::mojom::ShowState::FULLSCREEN));
+
+  properties[ui::mojom::WindowManager::kInitialDisplayId_Property] =
+      mojo::ConvertTo<std::vector<uint8_t>>(display_id);

[kylechar, 2016/11/23 00:28:00]

For the default value kInvalidDisplayId, do you really want to insert the
property with a value of -1? Or do you just want to not insert the property in
that case?

[thanhph, 2016/11/23 01:05:02]

Good question. I found a use case of kInvalidDisplayId here 
https://cs.chromium.org/chromium/src/ash/mus/property_util.cc?sq=package:chro...

which I interpret as we shouldn't add the property with a value of -1 since the
function GetInitialDisplayId will return -1 in this case. Since uint8_t is used,
I also assume display_id must be non negative, otherwise default display is used
to show window. If not correct, let me know. Thanks!

[kylechar, 2016/11/23 14:14:20]

So the value kInvalidDisplayId is appropriate to use to represent the concept of
"no display specified", since it's a reserved value that will never correspond
to a display. That part is fine.

I meant that if no display is specified then maybe it's better to not add that
property to the properties map, since it's meaningless. The value needs to be
serialized, deserialized, converted back to int64_t and then dropped (it's a lot
of work for nothing).

The last part about the value of |display_id| having to be non-negative is
wrong. |display_id| is int64_t or 8 bytes. It's being converted to a
std::vector<uint8_t>, not uint8_t, and I'd imagine you'll find that the vector
length is 8. All properties are just encoded into a vector of bytes (which are
represented by uint8_t).

+
   ui::Window* window = test_helper_->GetRootsOrderedByDisplayId()[0]
                            ->window_manager()
                            ->NewTopLevelWindow(&properties);
   window->SetVisible(true);
   return window;
 }
 
 ui::Window* WmTestBase::CreateChildTestWindow(ui::Window* parent,
                                               const gfx::Rect& bounds) {
   std::map<std::string, std::vector<uint8_t>> properties;
@@ skipping 16 matching lines @@
   test_helper_->Init();
 }
 
 void WmTestBase::TearDown() {
   teardown_called_ = true;
   test_helper_.reset();
 }
 
 }  // namespace mus
 }  // namespace ash