Cleanup: Fix base header include guards.

base/observer_list.h

 // 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.
 
-#ifndef BASE_OBSERVER_LIST_H__
-#define BASE_OBSERVER_LIST_H__
+#ifndef BASE_OBSERVER_LIST_H_
+#define BASE_OBSERVER_LIST_H_
 
 #include <algorithm>
 #include <limits>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 
 ///////////////////////////////////////////////////////////////////////////////
@@ skipping 216 matching lines @@
   do {                                                                   \
     if ((observer_list).might_have_observers()) {                        \
       ObserverListBase<ObserverType>::Iterator it_inside_observer_macro( \
           &observer_list);                                               \
       ObserverType* obs;                                                 \
       while ((obs = it_inside_observer_macro.GetNext()) != nullptr)         \
         obs->func;                                                       \
     }                                                                    \
   } while (0)
 
-#endif  // BASE_OBSERVER_LIST_H__
+#endif  // BASE_OBSERVER_LIST_H_