Fix leaks by removing preference observers. b=386665 r=tony@ponderer.org

browser/components/safebrowsing/content/phishing-warden.js

@@ -174,6 +174,7 @@ PROT_PhishingWarden.prototype.QueryInterface = function(iid) {
  * Cleanup on shutdown.
  */
 PROT_PhishingWarden.prototype.shutdown = function() {
+  this.prefs_.removeAllObservers();
   this.progressListener_.callback = null;
   this.progressListener_ = null;
   this.listManager_ = null;

toolkit/components/url-classifier/content/moz/preferences.js

@@ -209,6 +209,17 @@ G_Preferences.prototype.removeObserver = function(which, callback) {
   this.prefs_.removeObserver(which, observer);
 }
 
+/**
+ * Remove all preference observers registered through this object.
+ */
+G_Preferences.prototype.removeAllObservers = function() {
+  for (var which in this.observers_) {
+    for each (var observer in this.observers_[which].observers) {
+      this.prefs_.removeObserver(which, observer);
+    }
+  }
+  this.observers_ = {};
+}
 
 /**
  * Helper class that knows how to observe preference changes and