mash: Fix mash app shelf items; encapsulate ash property setup.

mash/example/window_type_launcher/window_type_launcher.cc

Index: mash/example/window_type_launcher/window_type_launcher.cc
diff --git a/mash/example/window_type_launcher/window_type_launcher.cc b/mash/example/window_type_launcher/window_type_launcher.cc
index 558a42c13d2f75c7c016f439470e8f4ae393d505..3614221b0716605861b725c389869ff29ef07101 100644
--- a/mash/example/window_type_launcher/window_type_launcher.cc
+++ b/mash/example/window_type_launcher/window_type_launcher.cc
@@ -6,6 +6,8 @@
 
 #include <stdint.h>
 
+#include "ash/public/cpp/shelf_types.h"
+#include "ash/public/cpp/window_properties.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
@@ -456,6 +458,7 @@ void WindowTypeLauncher::OnStart() {
   aura_init_ = base::MakeUnique<views::AuraInit>(
       context()->connector(), context()->identity(), "views_mus_resources.pak",
       std::string(), nullptr, views::AuraInit::Mode::AURA_MUS);
+  ash::RegisterWindowPropertiesForTransportAndMirroring();
 }
 
 void WindowTypeLauncher::OnBindInterface(
@@ -473,12 +476,17 @@ void WindowTypeLauncher::Launch(uint32_t what, mash::mojom::LaunchMode how) {
     windows_.back()->Activate();
     return;
   }
-  views::Widget* window = new views::Widget;
+  views::Widget* widget = new views::Widget;
   views::Widget::InitParams params(views::Widget::InitParams::TYPE_WINDOW);
   params.delegate = new WindowTypeLauncherView(this, context()->connector());
-  window->Init(params);
-  window->Show();
-  windows_.push_back(window);
+  widget->Init(params);
+  aura::Window* window = widget->GetNativeWindow();
+  const ash::ShelfID shelf_id("org.chromium.mash.window_type_launcher");

[msw, 2017/06/01 23:35:41]

q: I can't actually launch this from chrome --mash ToT; should I skip it?

+  window->SetProperty(ash::kShelfIDKey, new std::string(shelf_id.Serialize()));
+  window->SetProperty<int>(ash::kShelfItemTypeKey, ash::TYPE_DIALOG);
+
+  widget->Show();
+  windows_.push_back(widget);
 }
 
 void WindowTypeLauncher::Create(