Update from https://crrev.com/320343

base/observer_list_threadsafe.h

 // Copyright (c) 2012 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.
 
 #ifndef BASE_OBSERVER_LIST_THREADSAFE_H_
 #define BASE_OBSERVER_LIST_THREADSAFE_H_
 
 #include <algorithm>
 #include <map>
 
@@ skipping 181 matching lines @@
 
   struct ObserverListContext {
     explicit ObserverListContext(NotificationType type)
         : loop(base::MessageLoopProxy::current()),
           list(type) {
     }
 
     scoped_refptr<base::MessageLoopProxy> loop;
     ObserverList<ObserverType> list;
 
+   private:
     DISALLOW_COPY_AND_ASSIGN(ObserverListContext);
   };
 
   ~ObserverListThreadSafe() {
     STLDeleteValues(&observer_lists_);
   }
 
   // Wrapper which is called to fire the notifications for each thread's
   // ObserverList.  This function MUST be called on the thread which owns
   // the unsafe ObserverList.
   template <class Method, class Params>
   void NotifyWrapper(ObserverListContext* context,
       const UnboundMethod<ObserverType, Method, Params>& method) {
-
     // Check that this list still needs notifications.
     {
       base::AutoLock lock(list_lock_);
       typename ObserversListMap::iterator it =
           observer_lists_.find(base::PlatformThread::CurrentId());
 
       // The ObserverList could have been removed already.  In fact, it could
       // have been removed and then re-added!  If the master list's loop
       // does not match this one, then we do not need to finish this
       // notification.
       if (it == observer_lists_.end() || it->second != context)
         return;
     }
 
     {
-      typename ObserverList<ObserverType>::Iterator it(context->list);
+      typename ObserverList<ObserverType>::Iterator it(&context->list);
       ObserverType* obs;
       while ((obs = it.GetNext()) != NULL)
         method.Run(obs);
     }
 
     // If there are no more observers on the list, we can now delete it.
     if (context->list.size() == 0) {
       {
         base::AutoLock lock(list_lock_);
         // Remove |list| if it's not already removed.
@@ skipping 15 matching lines @@
       ObserversListMap;
 
   mutable base::Lock list_lock_;  // Protects the observer_lists_.
   ObserversListMap observer_lists_;
   const NotificationType type_;
 
   DISALLOW_COPY_AND_ASSIGN(ObserverListThreadSafe);
 };
 
 #endif  // BASE_OBSERVER_LIST_THREADSAFE_H_