views/mus: Have explicit ownership of views::WindowManagerConnection.

mash/catalog_viewer/catalog_viewer.h

Index: mash/catalog_viewer/catalog_viewer.h
diff --git a/mash/catalog_viewer/catalog_viewer.h b/mash/catalog_viewer/catalog_viewer.h
index 892847c9e5689c2aefb4bf41a2a02c76aae7a238..9f393f096d782db4962ee48e8c570820d3835c0b 100644
--- a/mash/catalog_viewer/catalog_viewer.h
+++ b/mash/catalog_viewer/catalog_viewer.h
@@ -18,6 +18,7 @@
 namespace views {
 class AuraInit;
 class Widget;
+class WindowManagerConnection;
 }
 
 namespace mash {
@@ -53,6 +54,7 @@ class CatalogViewer : public shell::ShellClient,
 
   mojo::TracingImpl tracing_;
   std::unique_ptr<views::AuraInit> aura_init_;
+  std::unique_ptr<views::WindowManagerConnection> window_manager_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(CatalogViewer);
 };