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

ash/sysui/sysui_application.cc

Index: ash/sysui/sysui_application.cc
diff --git a/ash/sysui/sysui_application.cc b/ash/sysui/sysui_application.cc
index 138355e299316f307f73c3140f0943d11d4e53c7..79ecd6fbcd015aeb0a0d1cc4403c73afd5e6e53d 100644
--- a/ash/sysui/sysui_application.cc
+++ b/ash/sysui/sysui_application.cc
@@ -217,7 +217,8 @@ class AshInit {
     InitializeResourceBundle(connector);
     aura_init_.reset(new views::AuraInit(connector, "views_mus_resources.pak"));
     MaterialDesignController::Initialize();
-    views::WindowManagerConnection::Create(connector, identity);
+    window_manager_connection_ =
+        views::WindowManagerConnection::Create(connector, identity);
 
     display::Screen* screen = display::Screen::GetScreen();
     DCHECK(screen);
@@ -300,6 +301,7 @@ class AshInit {
   std::unique_ptr<views::AuraInit> aura_init_;
   ShellDelegateMus* ash_delegate_ = nullptr;
   std::unique_ptr<NativeWidgetFactory> native_widget_factory_;
+  std::unique_ptr<views::WindowManagerConnection> window_manager_connection_;
 
   DISALLOW_COPY_AND_ASSIGN(AshInit);
 };