--- a/dom/media/MediaDecoderStateMachine.cpp
+++ b/dom/media/MediaDecoderStateMachine.cpp
@@ -13,17 +13,16 @@
 #include <algorithm>
 #include <stdint.h>
 
 #include "mediasink/AudioSink.h"
 #include "mediasink/AudioSinkWrapper.h"
 #include "mediasink/DecodedStream.h"
 #include "mediasink/OutputStreamManager.h"
 #include "mediasink/VideoSink.h"
-#include "mozilla/IndexSequence.h"
 #include "mozilla/Logging.h"
 #include "mozilla/MathAlgorithms.h"
 #include "mozilla/NotNull.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/SharedThreadPool.h"
 #include "mozilla/Sprintf.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/TaskQueue.h"
@@ -259,17 +258,17 @@ protected:
   const MediaInfo& Info() const { return mMaster->Info(); }
   MediaQueue<AudioData>& AudioQueue() const { return mMaster->mAudioQueue; }
   MediaQueue<VideoData>& VideoQueue() const { return mMaster->mVideoQueue; }
 
   template <class S, typename... Args, size_t... Indexes>
   auto
   CallEnterMemberFunction(S* aS,
                           Tuple<Args...>& aTuple,
-                          IndexSequence<Indexes...>)
+                          std::index_sequence<Indexes...>)
     -> decltype(ReturnTypeHelper(&S::Enter))
   {
     return aS->Enter(Move(Get<Indexes>(aTuple))...);
   }
 
   // Note this function will delete the current state object.
   // Don't access members to avoid UAF after this call.
   template <class S, typename... Ts>