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

mash/catalog_viewer/catalog_viewer.cc

Index: mash/catalog_viewer/catalog_viewer.cc
diff --git a/mash/catalog_viewer/catalog_viewer.cc b/mash/catalog_viewer/catalog_viewer.cc
index 0ecb86e1f000ad8060cbfcd7689bb37e0708bf6c..0aa4a241fa477e579a2d1354207957f586a8b4c9 100644
--- a/mash/catalog_viewer/catalog_viewer.cc
+++ b/mash/catalog_viewer/catalog_viewer.cc
@@ -182,7 +182,8 @@ void CatalogViewer::Initialize(shell::Connector* connector,
   tracing_.Initialize(connector, identity.name());
 
   aura_init_.reset(new views::AuraInit(connector, "views_mus_resources.pak"));
-  views::WindowManagerConnection::Create(connector, identity);
+  window_manager_connection_ =
+      views::WindowManagerConnection::Create(connector, identity);
 }
 
 bool CatalogViewer::AcceptConnection(shell::Connection* connection) {