--- a/dom/media/mediasink/AudioSink.cpp
+++ b/dom/media/mediasink/AudioSink.cpp
@@ -28,17 +28,17 @@ namespace media {
 // The amount of audio frames that is used to fuzz rounding errors.
 static const int64_t AUDIO_FUZZ_FRAMES = 1;
 
 // Amount of audio frames we will be processing ahead of use
 static const int32_t LOW_AUDIO_USECS = 300000;
 
 AudioSink::AudioSink(AbstractThread* aThread,
                      MediaQueue<AudioData>& aAudioQueue,
-                     TimeUnit aStartTime,
+                     const TimeUnit& aStartTime,
                      const AudioInfo& aInfo,
                      dom::AudioChannel aChannel)
   : mStartTime(aStartTime)
   , mInfo(aInfo)
   , mChannel(aChannel)
   , mPlaying(true)
   , mMonitor("AudioSink")
   , mWritten(0)

--- a/dom/media/mediasink/AudioSink.h
+++ b/dom/media/mediasink/AudioSink.h
@@ -27,17 +27,17 @@ class AudioConverter;
 namespace media {
 
 class AudioSink : private AudioStream::DataSource {
   using PlaybackParams = MediaSink::PlaybackParams;
 
 public:
   AudioSink(AbstractThread* aThread,
             MediaQueue<AudioData>& aAudioQueue,
-            TimeUnit aStartTime,
+            const TimeUnit& aStartTime,
             const AudioInfo& aInfo,
             dom::AudioChannel aChannel);
 
   ~AudioSink();
 
   // Return a promise which will be resolved when AudioSink
   // finishes playing, or rejected if any error.
   RefPtr<GenericPromise> Init(const PlaybackParams& aParams);