mandoline: write this after lunch.

mash/wm/window_manager_application.h

Index: mash/wm/window_manager_application.h
diff --git a/mash/wm/window_manager_application.h b/mash/wm/window_manager_application.h
index 39e04840e3c2bdb7c24d55b49448cb261044bc7b..95880a3122ec7819a293b6a435bc9ea23829fed7 100644
--- a/mash/wm/window_manager_application.h
+++ b/mash/wm/window_manager_application.h
@@ -18,6 +18,7 @@
 #include "mojo/application/public/cpp/application_delegate.h"
 #include "mojo/application/public/cpp/interface_factory_impl.h"
 #include "mojo/common/weak_binding_set.h"
+#include "mojo/services/tracing/public/cpp/tracing_impl.h"
 
 class BackgroundLayout;
 class ShelfLayout;
@@ -88,6 +89,8 @@ class WindowManagerApplication
 
   mojo::ApplicationImpl* app_;
 
+  mojo::TracingImpl tracing_;
+
   mus::mojom::WindowTreeHostPtr host_;
 
   scoped_ptr<ui::mojo::UIInit> ui_init_;