CameraPresenceNotifier observers removal supported.

chrome/browser/chromeos/camera_presence_notifier.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_CAMERA_PRESENCE_NOTIFIER_H_
 #define CHROME_BROWSER_CHROMEOS_CAMERA_PRESENCE_NOTIFIER_H_
 
 #include "base/memory/singleton.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/timer/timer.h"
 
 namespace chromeos {
 
 // Camera presence status dispatcher.
 class CameraPresenceNotifier {
  public:
   class Observer {
    public:
     virtual void OnCameraPresenceCheckDone(bool is_camera_present) = 0;
    protected:
-    virtual ~Observer() {}
+    virtual ~Observer() {
+      CameraPresenceNotifier::GetInstance()->RemoveObserver(this);

[Nikita (slow), 2014/04/03 11:47:29]

With virtual destructors all dtors for the type hierarchy will be called. This
means that you do need RemoveObserver() call only on the class that added itself
in AddObserver()

+    }
   };
 
   static CameraPresenceNotifier* GetInstance();
 
   void AddObserver(CameraPresenceNotifier::Observer* observer);
   void RemoveObserver(CameraPresenceNotifier::Observer* observer);
 
  private:
   friend struct DefaultSingletonTraits<CameraPresenceNotifier>;
   CameraPresenceNotifier();
@@ skipping 13 matching lines @@
 
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(CameraPresenceNotifier);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_CAMERA_PRESENCE_NOTIFIER_H_