Bug 350949. Feed leaks. Make sure the sync methods break the cycle with the SAX parser. r=vlad

toolkit/components/feeds/src/FeedProcessor.js

@@ -1152,11 +1152,13 @@ FeedProcessor.prototype = {
     this._init(uri);
     this._reader.parseFromStream(stream, null, stream.available(), 
                                  "application/xml");
+    this._reader = null;
   },
 
   parseFromString: function FP_parseFromString(inputString, uri) {
     this._init(uri);
-    this._reader.parseFromString(inputString,"application/xml");
+    this._reader.parseFromString(inputString, "application/xml");
+    this._reader = null;
   },
 
   parseAsync: function FP_parseAsync(requestObserver, uri) {