Backed out changeset 0813db72fe3e (bug 1125804) for bustage on a CLOSED TREE

dom/media/GraphDriver.cpp

@@ -612,8 +612,6 @@ AudioCallbackDriver::Init()
     mNextDriver->SetGraphTime(this, mIterationStart, mIterationEnd,
                                mStateComputedTime, mNextStateComputedTime);
     mGraphImpl->SetCurrentDriver(mNextDriver);
-    bool found = mGraphImpl->RemoveMixerCallback(this);
-    NS_WARN_IF_FALSE(!found, "Mixer callback not added when switching?");
     mNextDriver->Start();
     return;
   }

dom/media/MediaStreamGraphImpl.h

@@ -430,11 +430,6 @@ public:
     return mDriver;
   }
 
-  bool RemoveMixerCallback(MixerCallbackReceiver* aReceiver)
-  {
-    return mMixer.RemoveCallback(aReceiver);
-  }
-
   /**
    * Effectively set the new driver, while we are switching.
    * It is only safe to call this at the very end of an iteration, when there