Revert 88284 - Revert 88151 (see crbug.com/85296) - Fix user-after-free error with ObserverList. ...

base/observer_list_unittest.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/observer_list.h"
 #include "base/observer_list_threadsafe.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted.h"
@@ skipping 404 matching lines @@
   AddInClearObserve a(&observer_list);
 
   observer_list.AddObserver(&a);
 
   FOR_EACH_OBSERVER(Foo, observer_list, Observe(1));
   EXPECT_TRUE(a.added());
   EXPECT_EQ(0, a.adder().total)
       << "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