Use FFmpegVideoDecoder from a UtilityProcess

media/mojo/services/media_service_factory.cc

Index: media/mojo/services/media_service_factory.cc
diff --git a/media/mojo/services/media_service_factory.cc b/media/mojo/services/media_service_factory.cc
index 8c717010717be432173aa60c4370d082da4ac8cd..5404038d40d8f7f321319c2edebc85a6627daa46 100644
--- a/media/mojo/services/media_service_factory.cc
+++ b/media/mojo/services/media_service_factory.cc
@@ -8,6 +8,7 @@
 #include "base/memory/ptr_util.h"
 #include "media/mojo/services/media_service.h"
 #include "media/mojo/services/test_mojo_media_client.h"
+#include "media/mojo/services/utility_mojo_media_client.h"
 
 #if defined(OS_ANDROID)
 #include "media/mojo/services/android_mojo_media_client.h"  // nogncheck
@@ -32,4 +33,9 @@ std::unique_ptr<service_manager::Service> CreateMediaServiceForTesting() {
       new MediaService(base::MakeUnique<TestMojoMediaClient>()));
 }
 
+std::unique_ptr<service_manager::Service> CreateUtilityMediaService() {
+  return std::unique_ptr<service_manager::Service>(
+      new MediaService(base::MakeUnique<UtilityMojoMediaClient>()));
+}
+
 }  // namespace media