UMA stats for stylus usage

ash/mus/bridge/wm_window_mus.cc

Index: ash/mus/bridge/wm_window_mus.cc
diff --git a/ash/mus/bridge/wm_window_mus.cc b/ash/mus/bridge/wm_window_mus.cc
index 553dca55a9b8e92bb545b140ba2dfa91ebbdb133..efb3429640890c1411e8176a1750cbcb63a3ec68 100644
--- a/ash/mus/bridge/wm_window_mus.cc
+++ b/ash/mus/bridge/wm_window_mus.cc
@@ -220,6 +220,17 @@ ui::wm::WindowType WmWindowMus::GetType() const {
   return is_wm_window_type_set_ ? wm_window_type_ : GetWmWindowType(window_);
 }
 
+int WmWindowMus::GetAppType() const {
+  // TODO: Need support for window property kAppType: http://crbug.com/651206.
+  NOTIMPLEMENTED();
+  return 0;
+}
+
+void WmWindowMus::SetAppType(int app_type) const {
+  // TODO: Need support for window property kAppType: http://crbug.com/651206.
+  NOTIMPLEMENTED();
+}
+
 bool WmWindowMus::IsBubble() {
   return GetWindowType(window_) == ui::mojom::WindowType::BUBBLE;
 }