[Mojo Video Capture] Initialize COM on Windows

services/video_capture/service_impl.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_VIDEO_CAPTURE_SERVICE_IMPL_H_
 #define SERVICES_VIDEO_CAPTURE_SERVICE_IMPL_H_
 
 #include <memory>
 
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/service_manager/public/cpp/binder_registry.h"
 #include "services/service_manager/public/cpp/service.h"
 #include "services/service_manager/public/cpp/service_context_ref.h"
 #include "services/video_capture/public/interfaces/device_factory_provider.mojom.h"
 
+#if defined(OS_WIN)
+#include "base/win/scoped_com_initializer.h"
+#endif
+
 namespace video_capture {
 
 class ServiceImpl : public service_manager::Service {
  public:
   ServiceImpl();
   ~ServiceImpl() override;
 
   // service_manager::Service implementation.
   void OnStart() override;
   void OnBindInterface(const service_manager::BindSourceInfo& source_info,
                        const std::string& interface_name,
                        mojo::ScopedMessagePipeHandle interface_pipe) override;
   bool OnServiceManagerConnectionLost() override;
 
  private:
   void OnDeviceFactoryProviderRequest(
       const service_manager::BindSourceInfo& source_info,
       mojom::DeviceFactoryProviderRequest request);
   void SetShutdownDelayInSeconds(float seconds);
   void MaybeRequestQuitDelayed();
   void MaybeRequestQuit();
 
+#if defined(OS_WIN)
+  // COM must be initialized in order to access the video capture devices.
+  base::win::ScopedCOMInitializer com_initializer_;
+#endif
   float shutdown_delay_in_seconds_;
   service_manager::BinderRegistry registry_;
   std::unique_ptr<service_manager::ServiceContextRefFactory> ref_factory_;
   base::ThreadChecker thread_checker_;
   base::WeakPtrFactory<ServiceImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceImpl);
 };
 
 }  // namespace video_capture
 
 #endif  // SERVICES_VIDEO_CAPTURE_SERVICE_IMPL_H_