diff --git a/content/media/MediaDecoderReader.h b/content/media/MediaDecoderReader.h
index 2381c755f333..cd8733afe4f5 100644
--- a/content/media/MediaDecoderReader.h
+++ b/content/media/MediaDecoderReader.h
@@ -353,11 +353,13 @@ private:
 // done on the decode thread. Never hold the decoder monitor when
 // calling into this class. Unless otherwise specified, methods and fields of
 // this class can only be accessed on the decode thread.
-class MediaDecoderReader : public nsRunnable {
+class MediaDecoderReader {
 public:
   MediaDecoderReader(MediaDecoder* aDecoder);
   virtual ~MediaDecoderReader();
 
+  NS_INLINE_DECL_REFCOUNTING(MediaDecoderReader);
+
   // Initializes the reader, returns NS_OK on success, or NS_ERROR_FAILURE
   // on failure.
   virtual nsresult Init(MediaDecoderReader* aCloneDonor) = 0;