diff --git a/dom/media/MediaDecoder.cpp b/dom/media/MediaDecoder.cpp
index 2342621ff915..2c0fd8d70427 100644
--- a/dom/media/MediaDecoder.cpp
+++ b/dom/media/MediaDecoder.cpp
@@ -777,16 +777,16 @@ MediaDecoder::OnMetadataUpdate(TimedMetadata&& aMetadata)
 {
   MOZ_ASSERT(NS_IsMainThread());
   GetOwner()->RemoveMediaTracks();
-  MetadataLoaded(nsAutoPtr<MediaInfo>(new MediaInfo(*aMetadata.mInfo)),
-                 Move(aMetadata.mTags),
+  MetadataLoaded(MakeUnique<MediaInfo>(*aMetadata.mInfo),
+                 UniquePtr<MetadataTags>(aMetadata.mTags.forget()),
                  MediaDecoderEventVisibility::Observable);
   FirstFrameLoaded(Move(aMetadata.mInfo),
                    MediaDecoderEventVisibility::Observable);
 }
 
 void
-MediaDecoder::MetadataLoaded(nsAutoPtr<MediaInfo> aInfo,
-                             nsAutoPtr<MetadataTags> aTags,
+MediaDecoder::MetadataLoaded(UniquePtr<MediaInfo> aInfo,
+                             UniquePtr<MetadataTags> aTags,
                              MediaDecoderEventVisibility aEventVisibility)
 {
   MOZ_ASSERT(NS_IsMainThread());
@@ -798,15 +798,15 @@ MediaDecoder::MetadataLoaded(nsAutoPtr<MediaInfo> aInfo,
 
   mMediaSeekable = aInfo->mMediaSeekable;
   mMediaSeekableOnlyInBufferedRanges = aInfo->mMediaSeekableOnlyInBufferedRanges;
-  mInfo = aInfo.forget();
+  mInfo = aInfo.release();
   GetOwner()->ConstructMediaTracks(mInfo);
 
   // Make sure the element and the frame (if any) are told about
   // our new size.
   if (aEventVisibility != MediaDecoderEventVisibility::Suppressed) {
     mFiredMetadataLoaded = true;
-    GetOwner()->MetadataLoaded(mInfo,
-                               nsAutoPtr<const MetadataTags>(aTags.forget()));
+    GetOwner()->MetadataLoaded(
+      mInfo, nsAutoPtr<const MetadataTags>(aTags.release()));
   }
   // Invalidate() will end up calling GetOwner()->UpdateMediaSize with the last
   // dimensions retrieved from the video frame container. The video frame
diff --git a/dom/media/MediaDecoder.h b/dom/media/MediaDecoder.h
index 990085042af9..c3cd3eb32835 100644
--- a/dom/media/MediaDecoder.h
+++ b/dom/media/MediaDecoder.h
@@ -572,8 +572,8 @@ private:
 
   // Called when the metadata from the media file has been loaded by the
   // state machine. Call on the main thread only.
-  void MetadataLoaded(nsAutoPtr<MediaInfo> aInfo,
-                      nsAutoPtr<MetadataTags> aTags,
+  void MetadataLoaded(UniquePtr<MediaInfo> aInfo,
+                      UniquePtr<MetadataTags> aTags,
                       MediaDecoderEventVisibility aEventVisibility);
 
   MediaEventSource<void>*
diff --git a/dom/media/MediaDecoderStateMachine.cpp b/dom/media/MediaDecoderStateMachine.cpp
index d93e904078bd..694dd768b21f 100644
--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -2166,8 +2166,8 @@ DecodeMetadataState::OnMetadataRead(MetadataHolder&& aMetadata)
   MOZ_ASSERT(mMaster->mDuration.Ref().isSome());
 
   mMaster->mMetadataLoadedEvent.Notify(
-    nsAutoPtr<MediaInfo>(aMetadata.mInfo.release()),
-    nsAutoPtr<MetadataTags>(aMetadata.mTags.release()),
+    Move(aMetadata.mInfo),
+    Move(aMetadata.mTags),
     MediaDecoderEventVisibility::Observable);
 
   if (Info().IsEncrypted() && !mMaster->mCDMProxy) {
diff --git a/dom/media/MediaDecoderStateMachine.h b/dom/media/MediaDecoderStateMachine.h
index 1f17b54ffac9..64a09f8d4356 100644
--- a/dom/media/MediaDecoderStateMachine.h
+++ b/dom/media/MediaDecoderStateMachine.h
@@ -214,8 +214,8 @@ public:
 
   MediaEventSource<void>& OnMediaNotSeekable() const;
 
-  MediaEventSourceExc<nsAutoPtr<MediaInfo>,
-                      nsAutoPtr<MetadataTags>,
+  MediaEventSourceExc<UniquePtr<MediaInfo>,
+                      UniquePtr<MetadataTags>,
                       MediaDecoderEventVisibility>&
   MetadataLoadedEvent() { return mMetadataLoadedEvent; }
 
@@ -669,8 +669,8 @@ private:
   MediaEventListener mAudibleListener;
   MediaEventListener mOnMediaNotSeekable;
 
-  MediaEventProducerExc<nsAutoPtr<MediaInfo>,
-                        nsAutoPtr<MetadataTags>,
+  MediaEventProducerExc<UniquePtr<MediaInfo>,
+                        UniquePtr<MetadataTags>,
                         MediaDecoderEventVisibility> mMetadataLoadedEvent;
   MediaEventProducerExc<nsAutoPtr<MediaInfo>,
                         MediaDecoderEventVisibility> mFirstFrameLoadedEvent;