Fix user-after-free error with ObserverList. The problem is that if an ObserverListBase::Iterato...

base/observer_list_unittest.cc

Index: base/observer_list_unittest.cc
===================================================================
--- base/observer_list_unittest.cc	(revision 87996)
+++ base/observer_list_unittest.cc	(working copy)
@@ -422,4 +422,27 @@
       << "Adder should not observe, so sum should still be 0.";
 }
 
+class ListDestructor : public Foo {
+ public:
+  explicit ListDestructor(ObserverList<Foo>* list) : list_(list) {}
+  virtual void Observe(int x) {
+    delete list_;
+  }
+  virtual ~ListDestructor() { }
+  int total;
+ private:
+  ObserverList<Foo>* list_;
+};
+
+
+TEST(ObserverListTest, IteratorOutlivesList) {
+  ObserverList<Foo>* observer_list = new ObserverList<Foo>;
+  ListDestructor a(observer_list);
+  observer_list->AddObserver(&a);
+
+  FOR_EACH_OBSERVER(Foo, *observer_list, Observe(0));
+  // If this test fails, there'll be Valgrind errors when this function goes out
+  // of scope.
+}
+
 }  // namespace