Made ObserverListThreadSafe's destructor private since it's ref-counted.

base/observer_list_threadsafe.h

Index: base/observer_list_threadsafe.h
diff --git a/base/observer_list_threadsafe.h b/base/observer_list_threadsafe.h
index d034e6cd50255b81e891a123a4fa9fe0ee1b33a8..6085fde74ba9093ec59edf38e53c4f57eb65f7db 100644
--- a/base/observer_list_threadsafe.h
+++ b/base/observer_list_threadsafe.h
@@ -60,13 +60,6 @@ class ObserverListThreadSafe
       : type_(ObserverListBase<ObserverType>::NOTIFY_ALL) {}
   explicit ObserverListThreadSafe(NotificationType type) : type_(type) {}
 
-  ~ObserverListThreadSafe() {
-    typename ObserversListMap::const_iterator it;
-    for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it)
-      delete (*it).second;
-    observer_lists_.clear();
-  }
-
   // Add an observer to the list.
   void AddObserver(ObserverType* obs) {
     ObserverList<ObserverType>* list = NULL;
@@ -137,6 +130,15 @@ class ObserverListThreadSafe
   // TODO(mbelshe):  Add more wrappers for Notify() with more arguments.
 
  private:
+  friend class
+      base::RefCountedThreadSafe<ObserverListThreadSafe<ObserverType> >;
+  ~ObserverListThreadSafe() {
+    typename ObserversListMap::const_iterator it;
+    for (it = observer_lists_.begin(); it != observer_lists_.end(); ++it)
+      delete (*it).second;
+    observer_lists_.clear();
+  }
+
   template <class Method, class Params>
   void Notify(const UnboundMethod<ObserverType, Method, Params>& method) {
     AutoLock lock(list_lock_);