--- a/content/media/mediasource/MediaSource.cpp
+++ b/content/media/mediasource/MediaSource.cpp
@@ -101,16 +101,20 @@ MediaSource::Constructor(const GlobalObj
     aRv.Throw(NS_ERROR_UNEXPECTED);
     return nullptr;
   }
 
   nsRefPtr<MediaSource> mediaSource = new MediaSource(window);
   return mediaSource.forget();
 }
 
+MediaSource::~MediaSource()
+{
+}
+
 SourceBufferList*
 MediaSource::SourceBuffers()
 {
   MOZ_ASSERT_IF(mReadyState == MediaSourceReadyState::Closed, mSourceBuffers->IsEmpty());
   return mSourceBuffers;
 }
 
 SourceBufferList*

--- a/content/media/mediasource/MediaSource.h
+++ b/content/media/mediasource/MediaSource.h
@@ -45,16 +45,18 @@ template <typename T> class Optional;
 class MediaSource MOZ_FINAL : public DOMEventTargetHelper
 {
 public:
   /** WebIDL Methods. */
   static already_AddRefed<MediaSource>
   Constructor(const GlobalObject& aGlobal,
               ErrorResult& aRv);
 
+  ~MediaSource();
+
   SourceBufferList* SourceBuffers();
   SourceBufferList* ActiveSourceBuffers();
   MediaSourceReadyState ReadyState();
 
   double Duration();
   void SetDuration(double aDuration, ErrorResult& aRv);
 
   already_AddRefed<SourceBuffer> AddSourceBuffer(const nsAString& aType, ErrorResult& aRv);