ObserverList::HasObserver now takes a const pointer.

ash/wm/lock_state_controller.cc

 // Copyright 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 "ash/wm/lock_state_controller.h"
 
 #include <algorithm>
 #include <string>
 
 #include "ash/accessibility_delegate.h"
@@ skipping 67 matching lines @@
 }
 
 void LockStateController::AddObserver(LockStateObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void LockStateController::RemoveObserver(LockStateObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
-bool LockStateController::HasObserver(LockStateObserver* observer) {
+bool LockStateController::HasObserver(const LockStateObserver* observer) const {
   return observers_.HasObserver(observer);
 }
 
 void LockStateController::StartLockAnimation(
     bool shutdown_after_lock) {
   if (animating_lock_)
     return;
   shutdown_after_lock_ = shutdown_after_lock;
   can_cancel_lock_animation_ = true;
 
@@ skipping 466 matching lines @@
   if (unlocked_properties_.get() &&
       unlocked_properties_->background_is_hidden) {
     animation_sequence->StartAnimation(
         SessionStateAnimator::DESKTOP_BACKGROUND,
         SessionStateAnimator::ANIMATION_FADE_OUT,
         speed);
   }
 }
 
 }  // namespace ash