--- a/dom/html/HTMLMediaElement.cpp
+++ b/dom/html/HTMLMediaElement.cpp
@@ -2122,26 +2122,26 @@ NS_IMETHODIMP HTMLMediaElement::SetMuted
   } else {
     SetMutedInternal(mMuted & ~MUTED_BY_CONTENT);
   }
 
   DispatchAsyncEvent(NS_LITERAL_STRING("volumechange"));
   return NS_OK;
 }
 
-class HTMLMediaElement::CaptureStreamTrackSource :
+class HTMLMediaElement::DecoderCaptureTrackSource :
   public MediaStreamTrackSource,
   public DecoderPrincipalChangeObserver
 {
 public:
   NS_DECL_ISUPPORTS_INHERITED
-  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CaptureStreamTrackSource,
+  NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(DecoderCaptureTrackSource,
                                            MediaStreamTrackSource)
 
-  explicit CaptureStreamTrackSource(HTMLMediaElement* aElement)
+  explicit DecoderCaptureTrackSource(HTMLMediaElement* aElement)
     : MediaStreamTrackSource(nsCOMPtr<nsIPrincipal>(aElement->GetCurrentPrincipal()).get(),
                              true,
                              nsString())
     , mElement(aElement)
   {
     MOZ_ASSERT(mElement);
     mElement->AddDecoderPrincipalChangeObserver(this);
   }
@@ -2185,30 +2185,30 @@ public:
   {
     nsCOMPtr<nsIPrincipal> newPrincipal = mElement->GetCurrentPrincipal();
     if (nsContentUtils::CombineResourcePrincipals(&mPrincipal, newPrincipal)) {
       PrincipalChanged();
     }
   }
 
 protected:
-  virtual ~CaptureStreamTrackSource()
+  virtual ~DecoderCaptureTrackSource()
   {
   }
 
   RefPtr<HTMLMediaElement> mElement;
 };
 
-NS_IMPL_ADDREF_INHERITED(HTMLMediaElement::CaptureStreamTrackSource,
+NS_IMPL_ADDREF_INHERITED(HTMLMediaElement::DecoderCaptureTrackSource,
                          MediaStreamTrackSource)
-NS_IMPL_RELEASE_INHERITED(HTMLMediaElement::CaptureStreamTrackSource,
+NS_IMPL_RELEASE_INHERITED(HTMLMediaElement::DecoderCaptureTrackSource,
                           MediaStreamTrackSource)
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(HTMLMediaElement::CaptureStreamTrackSource)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(HTMLMediaElement::DecoderCaptureTrackSource)
 NS_INTERFACE_MAP_END_INHERITING(MediaStreamTrackSource)
-NS_IMPL_CYCLE_COLLECTION_INHERITED(HTMLMediaElement::CaptureStreamTrackSource,
+NS_IMPL_CYCLE_COLLECTION_INHERITED(HTMLMediaElement::DecoderCaptureTrackSource,
                                    MediaStreamTrackSource,
                                    mElement)
 
 class HTMLMediaElement::CaptureStreamTrackSourceGetter :
   public MediaStreamTrackSourceGetter
 {
 public:
   NS_DECL_ISUPPORTS_INHERITED
@@ -2222,17 +2222,17 @@ public:
   GetMediaStreamTrackSource(TrackID aInputTrackID) override
   {
     // We can return a new source each time here, even for different streams,
     // since the sources don't keep any internal state and all of them call
     // through to the same HTMLMediaElement.
     // If this changes (after implementing Stop()?) we'll have to ensure we
     // return the same source for all requests to the same TrackID, and only
     // have one getter.
-    return do_AddRef(new CaptureStreamTrackSource(mElement));
+    return do_AddRef(new DecoderCaptureTrackSource(mElement));
   }
 
 protected:
   virtual ~CaptureStreamTrackSourceGetter() {}
 
   RefPtr<HTMLMediaElement> mElement;
 };
 

--- a/dom/html/HTMLMediaElement.h
+++ b/dom/html/HTMLMediaElement.h
@@ -311,17 +311,17 @@ public:
 
   /**
    * Remove an added DecoderPrincipalChangeObserver from this media element.
    *
    * Returns true if it was successfully removed.
    */
   bool RemoveDecoderPrincipalChangeObserver(DecoderPrincipalChangeObserver* aObserver);
 
-  class CaptureStreamTrackSource;
+  class DecoderCaptureTrackSource;
   class CaptureStreamTrackSourceGetter;
 
   // Update the visual size of the media. Called from the decoder on the
   // main thread when/if the size changes.
   void UpdateMediaSize(const nsIntSize& aSize);
   // Like UpdateMediaSize, but only updates the size if no size has yet
   // been set.
   void UpdateInitialMediaSize(const nsIntSize& aSize);