Use MessageLoopProxy instead of MessageLoop to dispatch notifications in ObserverListThreadsafe.

base/observer_list_unittest.cc

Index: base/observer_list_unittest.cc
diff --git a/base/observer_list_unittest.cc b/base/observer_list_unittest.cc
index d0d2001e3f8dc0465b0236a702b56b192227ba3f..4539d2e6435fb5a95679ffea4209bcda1ed04c49 100644
--- a/base/observer_list_unittest.cc
+++ b/base/observer_list_unittest.cc
@@ -357,6 +357,18 @@ TEST(ObserverListThreadSafeTest, CrossThreadNotifications) {
   ThreadSafeObserverHarness(3, true);
 }
 
+TEST(ObserverListThreadSafeTest, OutlivesMessageLoop) {
+  MessageLoop* loop = new MessageLoop;
+  scoped_refptr<ObserverListThreadSafe<Foo> > observer_list(
+      new ObserverListThreadSafe<Foo>);
+
+  Adder a(1);
+  observer_list->AddObserver(&a);
+  delete loop;
+  // Test passes if we don't crash here.
+  observer_list->Notify(&Foo::Observe, 1);
+}
+
 TEST(ObserverListTest, Existing) {
   ObserverList<Foo> observer_list(ObserverList<Foo>::NOTIFY_EXISTING_ONLY);
   Adder a(1);