ObserverList::HasObserver now takes a const pointer.

components/invalidation/invalidator_registrar.cc

 // Copyright 2014 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 "components/invalidation/invalidator_registrar.h"
 
 #include <cstddef>
 #include <iterator>
 #include <utility>
 
@@ skipping 117 matching lines @@
   std::map<std::string, ObjectIdSet> clean_handlers_to_ids;
   for (HandlerIdsMap::const_iterator it = handler_to_ids_map_.begin();
        it != handler_to_ids_map_.end();
        ++it) {
     clean_handlers_to_ids[it->first->GetOwnerName()] = ObjectIdSet(it->second);
   }
   return clean_handlers_to_ids;
 }
 
 bool InvalidatorRegistrar::IsHandlerRegisteredForTest(
-    InvalidationHandler* handler) const {
+    const InvalidationHandler* handler) const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return handlers_.HasObserver(handler);
 }
 
 void InvalidatorRegistrar::DetachFromThreadForTest() {
   DCHECK(thread_checker_.CalledOnValidThread());
   thread_checker_.DetachFromThread();
 }
 
 }  // namespace syncer