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

services/ui/demo/mus_demo.h

Index: services/ui/demo/mus_demo.h
diff --git a/services/ui/demo/mus_demo.h b/services/ui/demo/mus_demo.h
index 78dbde7fb345bad159413ca3cd2b6813186afbd1..8957cc4f54fa4eeaa69a26ed8bfe70836ec81fe5 100644
--- a/services/ui/demo/mus_demo.h
+++ b/services/ui/demo/mus_demo.h
@@ -21,8 +21,6 @@
 
 namespace ui {
 class BitmapUploader;
-class GpuService;
-
 namespace demo {
 
 // A simple MUS Demo mojo app. This app connects to the mojo:ui, creates a new
@@ -71,7 +69,6 @@
 
   Window* window_ = nullptr;
   WindowTreeClient* window_tree_client_ = nullptr;
-  std::unique_ptr<GpuService> gpu_service_;
 
   // Used to send frames to mus.
   std::unique_ptr<ui::BitmapUploader> uploader_;