--- a/dom/media/mediasource/ContainerParser.cpp
+++ b/dom/media/mediasource/ContainerParser.cpp
@@ -358,33 +358,33 @@ private:
   Maybe<WebMTimeDataOffset> mLastMapping;
 };
 
 #ifdef MOZ_FMP4
 
 class MP4Stream : public mp4_demuxer::Stream
 {
 public:
-  explicit MP4Stream(MediaResource* aResource);
+  explicit MP4Stream(SourceBufferResource* aResource);
   virtual ~MP4Stream();
   bool ReadAt(int64_t aOffset,
               void* aBuffer,
               size_t aCount,
               size_t* aBytesRead) override;
   bool CachedReadAt(int64_t aOffset,
                     void* aBuffer,
                     size_t aCount,
                     size_t* aBytesRead) override;
   bool Length(int64_t* aSize) override;
 
 private:
-  MediaResourceIndex mResource;
+  RefPtr<SourceBufferResource> mResource;
 };
 
-MP4Stream::MP4Stream(MediaResource* aResource)
+MP4Stream::MP4Stream(SourceBufferResource* aResource)
   : mResource(aResource)
 {
   MOZ_COUNT_CTOR(MP4Stream);
   MOZ_ASSERT(aResource);
 }
 
 MP4Stream::~MP4Stream()
 {
@@ -401,32 +401,32 @@ MP4Stream::ReadAt(int64_t aOffset,
 }
 
 bool
 MP4Stream::CachedReadAt(int64_t aOffset,
                         void* aBuffer,
                         size_t aCount,
                         size_t* aBytesRead)
 {
-  nsresult rv = mResource.GetResource()->ReadFromCache(
+  nsresult rv = mResource->ReadFromCache(
     reinterpret_cast<char*>(aBuffer), aOffset, aCount);
   if (NS_FAILED(rv)) {
     *aBytesRead = 0;
     return false;
   }
   *aBytesRead = aCount;
   return true;
 }
 
 bool
 MP4Stream::Length(int64_t* aSize)
 {
-  if (mResource.GetLength() < 0)
+  if (mResource->GetLength() < 0)
     return false;
-  *aSize = mResource.GetLength();
+  *aSize = mResource->GetLength();
   return true;
 }
 
 class MP4ContainerParser : public ContainerParser
 {
 public:
   explicit MP4ContainerParser(const MediaContainerType& aType)
     : ContainerParser(aType)