mash: Add touch-hud app.

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 492053751f011d5726f7c01803357c05aef3d179..366cd5afda60c4e30574cb3592171f5f9e53448c 100644
--- a/ash/mus/test/wm_test_base.cc
+++ b/ash/mus/test/wm_test_base.cc
@@ -173,6 +173,18 @@ display::Display WmTestBase::GetSecondaryDisplay() {
   return window;
 }
 
+::ui::Window* WmTestBase::CreateFullscreenTestWindow() {
+  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));
+  ::ui::Window* window =
+      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;