Fixed to handle destroy callbacks better to unwind connections to image lib

git-svn-id: svn://10.0.0.236/trunk@27675 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/gfx/src/nsImageRequest.cpp

@@ -125,7 +125,9 @@ nsrefcnt ImageRequestImpl::Release(void)
       // Make sure dangling reference to this object goes away
       XP_RemoveObserver(mXPObserver, ns_observer_proc, (void*)this);
     }
-    IL_DestroyImage(mImageReq);
+    if (mImageReq) {
+      IL_DestroyImage(mImageReq);
+    }
     NS_DELETEXPCOM(this);
     return 0;
   }
@@ -346,7 +348,19 @@ static void ns_observer_proc (XP_Observable aSource,
    */
   if ((IL_IMAGE_DESTROYED == aMsg) && (nsnull != image_request)) {
     image_request->SetImageRequest(nsnull);
+    image_request->ImageDestroyed();
   }
 }
 
-
+void
+ImageRequestImpl::ImageDestroyed()
+{
+  if (mXPObserver) {
+    // Make sure dangling reference to this object goes
+    // away; this is just in case the image library changes
+    // and holds onto the observer list after destroying the
+    // image.
+    XP_RemoveObserver(mXPObserver, ns_observer_proc, (void*)this);
+    mXPObserver = nsnull;
+  }
+}

mozilla/gfx/src/nsImageRequest.h

@@ -58,10 +58,13 @@ public:
   // Interrupt loading of just this image.
   virtual void Interrupt();
 
+  // XXX These should go: fix ns_observer_proc to be a static method
   IL_ImageReq *GetImageRequest() { return mImageReq; }
   void SetImageRequest(IL_ImageReq *aImageReq) { mImageReq = aImageReq; }
   nsVoidArray *GetObservers() { return mObservers; }
 
+  void ImageDestroyed();
+
 private:
   IL_ImageReq *mImageReq;
   IL_GroupContext *mGroupContext;