diff --git a/dom/media/ChannelMediaDecoder.cpp b/dom/media/ChannelMediaDecoder.cpp
index b379e05df8fe..53b37647cd41 100644
--- a/dom/media/ChannelMediaDecoder.cpp
+++ b/dom/media/ChannelMediaDecoder.cpp
@@ -226,16 +226,6 @@ ChannelMediaDecoder::Shutdown()
   }
 }
 
-nsresult
-ChannelMediaDecoder::OpenResource(nsIStreamListener** aStreamListener)
-{
-  MOZ_ASSERT(NS_IsMainThread());
-  if (aStreamListener) {
-    *aStreamListener = nullptr;
-  }
-  return mResource->Open(aStreamListener);
-}
-
 nsresult
 ChannelMediaDecoder::Load(nsIChannel* aChannel,
                           bool aIsPrivateBrowsing,
@@ -243,6 +233,7 @@ ChannelMediaDecoder::Load(nsIChannel* aChannel,
 {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(!mResource);
+  MOZ_ASSERT(aStreamListener);
 
   mResource =
     BaseMediaResource::Create(mResourceCallback, aChannel, aIsPrivateBrowsing);
@@ -255,7 +246,7 @@ ChannelMediaDecoder::Load(nsIChannel* aChannel,
     return rv;
   }
 
-  rv = OpenResource(aStreamListener);
+  rv = mResource->Open(aStreamListener);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // Set mode to METADATA since we are about to read metadata.
diff --git a/dom/media/ChannelMediaDecoder.h b/dom/media/ChannelMediaDecoder.h
index 879cafff7c31..ce17b5abbe09 100644
--- a/dom/media/ChannelMediaDecoder.h
+++ b/dom/media/ChannelMediaDecoder.h
@@ -93,7 +93,6 @@ private:
   // Create a new state machine to run this decoder.
   MediaDecoderStateMachine* CreateStateMachine();
 
-  nsresult OpenResource(nsIStreamListener** aStreamListener);
   nsresult Load(BaseMediaResource* aOriginal);
 
   // Called by MediaResource when the download has ended.
diff --git a/dom/media/MediaCache.cpp b/dom/media/MediaCache.cpp
index ce87c17a05c8..482a70fd8b1a 100644
--- a/dom/media/MediaCache.cpp
+++ b/dom/media/MediaCache.cpp
@@ -2536,10 +2536,7 @@ nsresult
 MediaCacheStream::Init(int64_t aContentLength)
 {
   NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
-
-  if (mMediaCache) {
-    return NS_OK;
-  }
+  MOZ_ASSERT(!mMediaCache, "Has been initialized.");
 
   if (aContentLength > 0) {
     uint32_t length = uint32_t(std::min(aContentLength, int64_t(UINT32_MAX)));
diff --git a/dom/media/MediaResource.cpp b/dom/media/MediaResource.cpp
index f6c9f198a1e6..9f6fbf39818c 100644
--- a/dom/media/MediaResource.cpp
+++ b/dom/media/MediaResource.cpp
@@ -515,33 +515,27 @@ ChannelMediaResource::OnDataAvailable(nsIRequest* aRequest,
   return NS_OK;
 }
 
-nsresult ChannelMediaResource::Open(nsIStreamListener **aStreamListener)
+nsresult
+ChannelMediaResource::Open(nsIStreamListener** aStreamListener)
 {
   NS_ASSERTION(NS_IsMainThread(), "Only call on main thread");
+  MOZ_ASSERT(aStreamListener);
+  MOZ_ASSERT(mChannel);
 
   int64_t cl = -1;
-  if (mChannel) {
-    nsCOMPtr<nsIHttpChannel> hc = do_QueryInterface(mChannel);
-    if (hc && !IsPayloadCompressed(hc)) {
-      if (NS_FAILED(hc->GetContentLength(&cl))) {
-        cl = -1;
-      }
+  nsCOMPtr<nsIHttpChannel> hc = do_QueryInterface(mChannel);
+  if (hc && !IsPayloadCompressed(hc)) {
+    if (NS_FAILED(hc->GetContentLength(&cl))) {
+      cl = -1;
     }
   }
 
   nsresult rv = mCacheStream.Init(cl);
-  if (NS_FAILED(rv))
+  if (NS_FAILED(rv)) {
     return rv;
-  NS_ASSERTION(mOffset == 0, "Who set mOffset already?");
-
-  if (!mChannel) {
-    // When we're a clone, the decoder might ask us to Open even though
-    // we haven't established an mChannel (because we might not need one)
-    NS_ASSERTION(!aStreamListener,
-                 "Should have already been given a channel if we're to return a stream listener");
-    return NS_OK;
   }
 
+  MOZ_ASSERT(mOffset == 0, "Who set mOffset already?");
   return OpenChannel(aStreamListener);
 }