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

services/ui/common/gpu_service.h

Index: services/ui/common/gpu_service.h
diff --git a/services/ui/common/gpu_service.h b/services/ui/common/gpu_service.h
index d00a60c4ce1b1e77a96807bfdc94a359f53dc8aa..7308754eac55f45c1c5ac0d7b234f8e75e16e9cd 100644
--- a/services/ui/common/gpu_service.h
+++ b/services/ui/common/gpu_service.h
@@ -27,8 +27,6 @@
 
 class MUS_COMMON_EXPORT GpuService : public gpu::GpuChannelHostFactory {
  public:
-  ~GpuService() override;
-
   void EstablishGpuChannel(const base::Closure& callback);
   scoped_refptr<gpu::GpuChannelHost> EstablishGpuChannelSync();
   scoped_refptr<gpu::GpuChannelHost> GetGpuChannel();
@@ -38,13 +36,16 @@
 
   // The GpuService has to be initialized in the main thread before establishing
   // the gpu channel.
-  static std::unique_ptr<GpuService> Initialize(shell::Connector* connector);
+  static void Initialize(shell::Connector* connector);
+  // The GpuService has to be terminated in the main thread.
+  static void Terminate();
   static GpuService* GetInstance();
 
  private:
   friend struct base::DefaultSingletonTraits<GpuService>;
 
   explicit GpuService(shell::Connector* connector);
+  ~GpuService() override;
 
   scoped_refptr<gpu::GpuChannelHost> GetGpuChannelLocked();
   void EstablishGpuChannelOnMainThread();