media: Make MediaKeys ref-counted.

media/cdm/default_cdm_factory.cc

Index: media/cdm/default_cdm_factory.cc
diff --git a/media/cdm/default_cdm_factory.cc b/media/cdm/default_cdm_factory.cc
index c025fe982db83ee919a8d57b6bad1c923666d5a5..675cb0558647bd239bebb7dd942616d6556a26f7 100644
--- a/media/cdm/default_cdm_factory.cc
+++ b/media/cdm/default_cdm_factory.cc
@@ -43,11 +43,11 @@ void DefaultCdmFactory::Create(
     return;
   }
 
-  scoped_ptr<MediaKeys> cdm(
+  scoped_refptr<MediaKeys> cdm(
       new AesDecryptor(security_origin, session_message_cb, session_closed_cb,
                        session_keys_change_cb));
   base::ThreadTaskRunnerHandle::Get()->PostTask(
-      FROM_HERE, base::Bind(cdm_created_cb, base::Passed(&cdm), ""));
+      FROM_HERE, base::Bind(cdm_created_cb, cdm, ""));
 }
 
 }  // namespace media