image_decoder: Delay shutdown on idle

services/image_decoder/image_decoder_service.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SERVICES_IMAGE_DECODER_IMAGE_DECODER_SERVICE_H_
 #define SERVICES_IMAGE_DECODER_IMAGE_DECODER_SERVICE_H_
 
 #include <memory>
 
 #include "base/callback.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "services/service_manager/public/cpp/service.h"
 #include "services/service_manager/public/cpp/service_context_ref.h"
 
 namespace image_decoder {
 
 class ImageDecoderService : public service_manager::Service {
  public:
   ImageDecoderService();
   ~ImageDecoderService() override;
 
   // Factory function for use as an embedded service.
   static std::unique_ptr<service_manager::Service> Create();
 
   // service_manager::Service:
   void OnStart() override;
   bool OnConnect(const service_manager::ServiceInfo& remote_info,
                  service_manager::InterfaceRegistry* registry) override;
   bool OnStop() override;
 
  private:
+  void MaybeRequestQuitDelayed();
+  void MaybeRequestQuit();
+
   std::unique_ptr<service_manager::ServiceContextRefFactory> ref_factory_;
+  base::WeakPtrFactory<ImageDecoderService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageDecoderService);
 };
 
 }  // namespace image_decoder
 
 #endif  // SERVICES_IMAGE_DECODER_IMAGE_DECODER_SERVICE_H_