ObserverList::HasObserver now takes a const pointer.

chromeos/dbus/power_manager_client.h

 // 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.
 
 #ifndef CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_
 #define CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 82 matching lines @@
         const base::TimeDelta& time_until_idle_action) {}
 
     // Called after IdleActionImminent() when the inactivity timer is reset
     // before the idle action has been performed.
     virtual void IdleActionDeferred() {}
   };
 
   // Adds and removes the observer.
   virtual void AddObserver(Observer* observer) = 0;
   virtual void RemoveObserver(Observer* observer) = 0;
-  virtual bool HasObserver(Observer* observer) = 0;
+  virtual bool HasObserver(const Observer* observer) const = 0;
 
   // Decreases the screen brightness. |allow_off| controls whether or not
   // it's allowed to turn off the back light.
   virtual void DecreaseScreenBrightness(bool allow_off) = 0;
 
   // Increases the screen brightness.
   virtual void IncreaseScreenBrightness() = 0;
 
   // Set the screen brightness to |percent|, in the range [0.0, 100.0].
   // If |gradual| is true, the transition will be animated.
@@ skipping 57 matching lines @@
   // Create() should be used instead.
   PowerManagerClient();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PowerManagerClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_POWER_MANAGER_CLIENT_H_