mash: Add touch-hud app.

mash/app_driver/app_driver.cc

Index: mash/app_driver/app_driver.cc
diff --git a/mash/app_driver/app_driver.cc b/mash/app_driver/app_driver.cc
index 4947911b3c28975665c8f0574ad094cc91a4ded4..2e549fa471f1e9051681d7efc93e05333c52a98e 100644
--- a/mash/app_driver/app_driver.cc
+++ b/mash/app_driver/app_driver.cc
@@ -25,6 +25,7 @@ enum class Accelerator : uint32_t {
   NewChromeTab,
   NewChromeIncognitoWindow,
   ShowTaskManager,
+  ToggleTouchHud,
 };
 
 struct AcceleratorSpec {
@@ -44,6 +45,8 @@ AcceleratorSpec g_spec[] = {
      ui::mojom::kEventFlagControlDown | ui::mojom::kEventFlagShiftDown},
     {Accelerator::ShowTaskManager, ui::mojom::KeyboardCode::ESCAPE,
      ui::mojom::kEventFlagShiftDown},
+    {Accelerator::ToggleTouchHud, ui::mojom::KeyboardCode::P,
+     ui::mojom::kEventFlagControlDown | ui::mojom::kEventFlagAltDown},
 };
 
 void AssertTrue(bool success) {
@@ -118,6 +121,8 @@ void AppDriver::OnAccelerator(uint32_t id, std::unique_ptr<ui::Event> event) {
        {mojom::kIncognitoWindow, "exe:chrome", LaunchMode::MAKE_NEW}},
       {Accelerator::ShowTaskManager,
        {mojom::kWindow, "mojo:task_viewer", LaunchMode::DEFAULT}},
+      {Accelerator::ToggleTouchHud,
+       {mojom::kWindow, "mojo:touch_hud", LaunchMode::DEFAULT}},
   };
 
   const auto iter = options.find(static_cast<Accelerator>(id));