ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/cras_audio_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/cras_audio_client.h"
 
 #include "base/bind.h"
 #include "base/format_macros.h"
 #include "base/strings/stringprintf.h"
 #include "dbus/bus.h"
@@ skipping 18 matching lines @@
 
   // CrasAudioClient overrides:
   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 GetVolumeState(const GetVolumeStateCallback& callback) override {
     dbus::MethodCall method_call(cras::kCrasControlInterface,
                                  cras::kGetVolumeState);
     cras_proxy_->CallMethod(
         &method_call,
         dbus::ObjectProxy::TIMEOUT_USE_DEFAULT,
         base::Bind(&CrasAudioClientImpl::OnGetVolumeState,
@@ skipping 401 matching lines @@
 
 CrasAudioClient::~CrasAudioClient() {
 }
 
 // static
 CrasAudioClient* CrasAudioClient::Create() {
   return new CrasAudioClientImpl();
 }
 
 }  // namespace chromeos