ObserverList::HasObserver now takes a const pointer.

chrome/browser/sync/backend_migrator.cc

 // 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.
 
 #include "chrome/browser/sync/backend_migrator.h"
 
 #include "base/message_loop/message_loop.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/tracked_objects.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 57 matching lines @@
   DCHECK_GT(state_, WAITING_TO_START);
   // If we're already migrating, interrupt the current migration.
   RestartMigration();
 }
 
 void BackendMigrator::AddMigrationObserver(MigrationObserver* observer) {
   migration_observers_.AddObserver(observer);
 }
 
 bool BackendMigrator::HasMigrationObserver(
-    MigrationObserver* observer) const {
+    const MigrationObserver* observer) const {
   return migration_observers_.HasObserver(observer);
 }
 
 void BackendMigrator::RemoveMigrationObserver(MigrationObserver* observer) {
   migration_observers_.RemoveObserver(observer);
 }
 
 void BackendMigrator::ChangeState(State new_state) {
   state_ = new_state;
   FOR_EACH_OBSERVER(MigrationObserver, migration_observers_,
@@ skipping 127 matching lines @@
 
 syncer::ModelTypeSet BackendMigrator::GetPendingMigrationTypesForTest() const {
   return to_migrate_;
 }
 
 #undef SDVLOG
 
 #undef SLOG
 
 };  // namespace browser_sync