Fix autoupdate_EndToEndTest on veyron_rialto

base/callback_list.h

 // Copyright 2013 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_CALLBACK_LIST_H_
 #define BASE_CALLBACK_LIST_H_
 
 #include <list>
 #include <memory>
 
@@ skipping 102 matching lines @@
     removal_callback_ = callback;
   }
 
   // Returns true if there are no subscriptions. This is only valid to call when
   // not looping through the list.
   bool empty() {
     DCHECK_EQ(0, active_iterator_count_);
     return callbacks_.empty();
   }
 
+  // Clears all the callbacks from this list.
+  void ClearAll() { callbacks_.clear(); }
+
  protected:
   // An iterator class that can be used to access the list of callbacks.
   class Iterator {
    public:
     explicit Iterator(CallbackListBase<CallbackType>* list)
         : list_(list),
           list_iter_(list_->callbacks_.begin()) {
       ++list_->active_iterator_count_;
     }
 
@@ skipping 87 matching lines @@
     }
   }
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CallbackList);
 };
 
 }  // namespace base
 
 #endif  // BASE_CALLBACK_LIST_H_