Bug 865550 - Unlink AudioBufferSourceNode members before AudioNode; r=mccr8

Author: Ehsan Akhgari

content/media/webaudio/AudioBufferSourceNode.cpp

@@ -17,13 +17,13 @@
 namespace mozilla {
 namespace dom {
 
-NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(AudioBufferSourceNode, AudioNode)
+NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(AudioBufferSourceNode)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mBuffer)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mPlaybackRate)
   if (tmp->Context()) {
     tmp->Context()->UnregisterAudioBufferSourceNode(tmp);
   }
-NS_IMPL_CYCLE_COLLECTION_UNLINK_END
+NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(AudioNode)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(AudioBufferSourceNode, AudioNode)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mBuffer)

xpcom/glue/nsCycleCollectionParticipant.h

@@ -381,6 +381,12 @@ T* DowncastCCParticipant(void *p)
 
 ///////////////////////////////////////////////////////////////////////////////
 // Helpers for implementing nsCycleCollectionParticipant::Unlink
+//
+// You need to use NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED if you want
+// the base class Unlink version to be called before your own implementation.
+// You can use NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED if you want the
+// base class Unlink to get called after your own implementation.  You should
+// never use them together.
 ///////////////////////////////////////////////////////////////////////////////
 
 #define NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class)                          \
@@ -402,6 +408,13 @@ T* DowncastCCParticipant(void *p)
     return NS_OK;                                                              \
   }
 
+#define NS_IMPL_CYCLE_COLLECTION_UNLINK_END_INHERITED(_base_class)             \
+    nsISupports *s = static_cast<nsISupports*>(p);                             \
+    NS_CYCLE_COLLECTION_CLASSNAME(_base_class)::UnlinkImpl(s);                 \
+    (void)tmp;                                                                 \
+    return NS_OK;                                                              \
+  }
+
 #define NS_IMPL_CYCLE_COLLECTION_UNLINK_0(_class)                              \
   NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(_class)                                \
   NS_IMPL_CYCLE_COLLECTION_UNLINK_END