ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/system_clock_client.cc

 // Copyright (c) 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.
 
 #include "chromeos/dbus/system_clock_client.h"
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/observer_list.h"
 #include "dbus/bus.h"
@@ skipping 17 matching lines @@
   }
 
   virtual void AddObserver(Observer* observer) override {
     observers_.AddObserver(observer);
   }
 
   virtual void RemoveObserver(Observer* observer) override {
     observers_.RemoveObserver(observer);
   }
 
-  virtual bool HasObserver(Observer* observer) override {
+  virtual bool HasObserver(const Observer* observer) const override {
     return observers_.HasObserver(observer);
   }
 
   virtual void SetTime(int64 time_in_seconds) override {
     // Always try to set the time, because |can_set_time_| may be stale.
     dbus::MethodCall method_call(system_clock::kSystemClockInterface,
                                  system_clock::kSystemClockSet);
     dbus::MessageWriter writer(&method_call);
     writer.AppendInt64(time_in_seconds);
     system_clock_proxy_->CallMethod(&method_call,
@@ skipping 102 matching lines @@
 
 SystemClockClient::~SystemClockClient() {
 }
 
 // static
 SystemClockClient* SystemClockClient::Create() {
   return new SystemClockClientImpl();
 }
 
 }  // namespace chromeos