Support creation of toplevel mus::Windows on separate displays

ash/mus/test/wm_test_base.cc

Index: ash/mus/test/wm_test_base.cc
diff --git a/ash/mus/test/wm_test_base.cc b/ash/mus/test/wm_test_base.cc
index c45eb6e73457fd27f8e573754940c7f90f90f533..7b0d70a851c659ab6afbdc96cab717ac0f569d02 100644
--- a/ash/mus/test/wm_test_base.cc
+++ b/ash/mus/test/wm_test_base.cc
@@ -94,6 +94,19 @@ display::Display WmTestBase::GetSecondaryDisplay() {
   return roots.size() < 2 ? display::Display() : roots[1]->display();
 }
 
+RootWindowController* WmTestBase::GetPrimaryRootWindowController() {
+  std::vector<RootWindowController*> roots =
+      test_helper_->GetRootsOrderedByDisplayId();
+  DCHECK(!roots.empty());
+  return roots[0];
+}
+
+RootWindowController* WmTestBase::GetSecondaryRootWindowController() {
+  std::vector<RootWindowController*> roots =
+      test_helper_->GetRootsOrderedByDisplayId();
+  return roots.size() < 2 ? nullptr : roots[1];
+}
+
 ui::Window* WmTestBase::CreateTestWindow(const gfx::Rect& bounds) {
   return CreateTestWindow(bounds, ui::wm::WINDOW_TYPE_NORMAL);
 }
@@ -135,6 +148,19 @@ ui::Window* WmTestBase::CreateFullscreenTestWindow() {
   return window;
 }
 
+ui::Window* WmTestBase::CreateFullscreenTestWindow(RootWindowController* root) {
+  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>>(root->display().id());
+
+  ui::Window* window = root->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;