--- a/image/src/imgStatusTracker.cpp
+++ b/image/src/imgStatusTracker.cpp
@@ -14,213 +14,16 @@
 #include "nsNetUtil.h"
 #include "nsIObserverService.h"
 
 #include "mozilla/Assertions.h"
 #include "mozilla/Services.h"
 
 using namespace mozilla::image;
 
-class imgStatusTrackerNotifyingObserver : public imgDecoderObserver
-{
-public:
-  imgStatusTrackerNotifyingObserver(imgStatusTracker* aTracker)
-  : mTracker(aTracker)
-  {
-    MOZ_ASSERT(aTracker);
-  }
-
-  virtual ~imgStatusTrackerNotifyingObserver() {}
-
-  void SetTracker(imgStatusTracker* aTracker)
-  {
-    MOZ_ASSERT(aTracker);
-    mTracker = aTracker;
-  }
-
-  /** imgDecoderObserver methods **/
-
-  virtual void OnStartDecode()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::OnStartDecode");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnStartDecode callback before we've created our image");
-
-    mTracker->RecordStartDecode();
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendStartDecode(iter.GetNext());
-    }
-
-    if (!mTracker->IsMultipart()) {
-      mTracker->RecordBlockOnload();
-
-      nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-      while (iter.HasMore()) {
-        mTracker->SendBlockOnload(iter.GetNext());
-      }
-    }
-  }
-
-  virtual void OnStartRequest()
-  {
-    NS_NOTREACHED("imgStatusTrackerNotifyingObserver(imgDecoderObserver)::OnStartRequest");
-  }
-
-  virtual void OnStartContainer()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::OnStartContainer");
-
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnStartContainer callback before we've created our image");
-    {
-      nsRefPtr<Image> image = mTracker->GetImage();
-      mTracker->RecordStartContainer(image);
-    }
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendStartContainer(iter.GetNext());
-    }
-  }
-
-  virtual void OnStartFrame()
-  {
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::OnStartFrame");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnStartFrame callback before we've created our image");
-
-    mTracker->RecordStartFrame();
-
-    // This is not observed below the imgStatusTracker level, so we don't need
-    // to SendStartFrame.
-  }
-
-  virtual void FrameChanged(const nsIntRect* dirtyRect)
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::FrameChanged");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "FrameChanged callback before we've created our image");
-
-    mTracker->RecordFrameChanged(dirtyRect);
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendFrameChanged(iter.GetNext(), dirtyRect);
-    }
-  }
-
-  virtual void OnStopFrame()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::OnStopFrame");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnStopFrame callback before we've created our image");
-
-    mTracker->RecordStopFrame();
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendStopFrame(iter.GetNext());
-    }
-
-    mTracker->MaybeUnblockOnload();
-  }
-
-  virtual void OnStopDecode(nsresult aStatus)
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    LOG_SCOPE(GetImgLog(), "imgStatusTrackerNotifyingObserver::OnStopDecode");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnStopDecode callback before we've created our image");
-
-    bool preexistingError = mTracker->GetImageStatus() == imgIRequest::STATUS_ERROR;
-
-    mTracker->RecordStopDecode(aStatus);
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendStopDecode(iter.GetNext(), aStatus);
-    }
-
-    // This is really hacky. We need to handle the case where we start decoding,
-    // block onload, but then hit an error before we get to our first frame.
-    mTracker->MaybeUnblockOnload();
-
-    if (NS_FAILED(aStatus) && !preexistingError) {
-      mTracker->FireFailureNotification();
-    }
-  }
-
-  virtual void OnStopRequest(bool aLastPart, nsresult aStatus)
-  {
-    NS_NOTREACHED("imgStatusTrackerNotifyingObserver(imgDecoderObserver)::OnStopRequest");
-  }
-
-  virtual void OnDiscard()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnDiscard callback before we've created our image");
-
-    mTracker->RecordDiscard();
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendDiscard(iter.GetNext());
-    }
-  }
-
-  virtual void OnUnlockedDraw()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnUnlockedDraw callback before we've created our image");
-    mTracker->RecordUnlockedDraw();
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendUnlockedDraw(iter.GetNext());
-    }
-  }
-
-  virtual void OnImageIsAnimated()
-  {
-    MOZ_ASSERT(NS_IsMainThread(),
-               "Use imgStatusTracker::mConsumers on main thread only");
-    NS_ABORT_IF_FALSE(mTracker->HasImage(),
-                      "OnImageIsAnimated callback before we've created our image");
-    mTracker->RecordImageIsAnimated();
-
-    nsTObserverArray<imgRequestProxy*>::ForwardIterator iter(mTracker->mConsumers);
-    while (iter.HasMore()) {
-      mTracker->SendImageIsAnimated(iter.GetNext());
-    }
-  }
-
-  virtual void OnError()
-  {
-    mTracker->RecordError();
-  }
-
-private:
-  nsRefPtr<imgStatusTracker> mTracker;
-};
-
 class imgStatusTrackerObserver : public imgDecoderObserver
 {
 public:
   imgStatusTrackerObserver(imgStatusTracker* aTracker)
   : mTracker(aTracker->asWeakPtr())
   {
     MOZ_ASSERT(aTracker);
   }

--- a/image/src/imgStatusTracker.h
+++ b/image/src/imgStatusTracker.h
@@ -8,17 +8,16 @@
 #define imgStatusTracker_h__
 
 class imgDecoderObserver;
 class imgIContainer;
 class imgRequestProxy;
 class imgStatusNotifyRunnable;
 class imgRequestNotifyRunnable;
 class imgStatusTrackerObserver;
-class imgStatusTrackerNotifyingObserver;
 class nsIRunnable;
 
 #include "mozilla/RefPtr.h"
 #include "mozilla/WeakPtr.h"
 #include "nsCOMPtr.h"
 #include "nsTObserverArray.h"
 #include "nsThreadUtils.h"
 #include "nsRect.h"
@@ -294,17 +293,16 @@ public:
   void SyncNotifyDifference(const mozilla::image::ImageStatusDiff& aDiff);
 
   nsIntRect GetInvalidRect() const { return mInvalidRect; }
 
 private:
   friend class imgStatusNotifyRunnable;
   friend class imgRequestNotifyRunnable;
   friend class imgStatusTrackerObserver;
-  friend class imgStatusTrackerNotifyingObserver;
   friend class imgStatusTrackerInit;
   imgStatusTracker(const imgStatusTracker& aOther);
 
   // Main thread only because it deals with the observer service.
   void FireFailureNotification();
 
   // Main thread only, since imgRequestProxy calls are expected on the main
   // thread, and mConsumers is not threadsafe.