Revert of services/ui: Have an explicit lifetime/ownership of ui::GpuService.

ui/views/mus/window_manager_connection.h

Index: ui/views/mus/window_manager_connection.h
diff --git a/ui/views/mus/window_manager_connection.h b/ui/views/mus/window_manager_connection.h
index 69291f7da625dc031173fbce3416d6393579d3ff..867e97b4522a1dcd7fe157b571c1a7c6d6441807 100644
--- a/ui/views/mus/window_manager_connection.h
+++ b/ui/views/mus/window_manager_connection.h
@@ -22,10 +22,6 @@
 
 namespace shell {
 class Connector;
-}
-
-namespace ui {
-class GpuService;
 }
 
 namespace views {
@@ -100,7 +96,6 @@
   shell::Identity identity_;
   std::unique_ptr<ScreenMus> screen_;
   std::unique_ptr<ui::WindowTreeClient> client_;
-  std::unique_ptr<ui::GpuService> gpu_service_;
   // Must be empty on destruction.
   base::ObserverList<PointerWatcher, true> pointer_watchers_;
   base::ObserverList<TouchEventWatcher, true> touch_event_watchers_;