--- a/dom/media/MediaDecoderReaderWrapper.cpp
+++ b/dom/media/MediaDecoderReaderWrapper.cpp
@@ -164,24 +164,16 @@ MediaDecoderReaderWrapper::ReadMetadata(
   return InvokeAsync(mReader->OwnerThread(), mReader.get(), __func__,
                      &MediaDecoderReader::AsyncReadMetadata)
          ->Then(mOwnerThread, __func__, this,
                 &MediaDecoderReaderWrapper::OnMetadataRead,
                 &MediaDecoderReaderWrapper::OnMetadataNotRead)
          ->CompletionPromise();
 }
 
-RefPtr<HaveStartTimePromise>
-MediaDecoderReaderWrapper::AwaitStartTime()
-{
-  MOZ_ASSERT(mOwnerThread->IsCurrentThreadIn());
-  MOZ_ASSERT(!mShutdown);
-  return mStartTimeRendezvous->AwaitStartTime();
-}
-
 void
 MediaDecoderReaderWrapper::RequestAudioData()
 {
   MOZ_ASSERT(mOwnerThread->IsCurrentThreadIn());
   MOZ_ASSERT(!mShutdown);
 
   auto p = InvokeAsync(mReader->OwnerThread(), mReader.get(), __func__,
                        &MediaDecoderReader::RequestAudioData);

--- a/dom/media/MediaDecoderReaderWrapper.h
+++ b/dom/media/MediaDecoderReaderWrapper.h
@@ -47,17 +47,16 @@ private:
   MediaCallbackExc<WaitCallbackData> mVideoWaitCallback;
 
 public:
   MediaDecoderReaderWrapper(AbstractThread* aOwnerThread,
                             MediaDecoderReader* aReader);
 
   media::TimeUnit StartTime() const;
   RefPtr<MetadataPromise> ReadMetadata();
-  RefPtr<HaveStartTimePromise> AwaitStartTime();
 
   decltype(mAudioCallback)& AudioCallback() { return mAudioCallback; }
   decltype(mVideoCallback)& VideoCallback() { return mVideoCallback; }
   decltype(mAudioWaitCallback)& AudioWaitCallback() { return mAudioWaitCallback; }
   decltype(mVideoWaitCallback)& VideoWaitCallback() { return mVideoWaitCallback; }
 
   // NOTE: please set callbacks before requesting audio/video data!
   void RequestAudioData();