Remove usage of base::ObserverList<T>::Iter::GetNext() in //ui.

ui/compositor/layer_animator.cc

 // 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.
 
 #include "ui/compositor/layer_animator.h"
 
 #include <stddef.h>
 
 #include <memory>
 
@@ skipping 854 matching lines @@
 
 void LayerAnimator::GetTargetValue(
     LayerAnimationElement::TargetValue* target) const {
   for (AnimationQueue::const_iterator iter = animation_queue_.begin();
        iter != animation_queue_.end(); ++iter) {
     (*iter)->GetTargetValue(target);
   }
 }
 
 void LayerAnimator::OnScheduled(LayerAnimationSequence* sequence) {
-  if (observers_.might_have_observers()) {
-    base::ObserverListBase<LayerAnimationObserver>::Iterator it(&observers_);
-    LayerAnimationObserver* obs;
-    while ((obs = it.GetNext()) != NULL) {
-      sequence->AddObserver(obs);
-    }
-  }
+  for (LayerAnimationObserver& observer : observers_)
+    sequence->AddObserver(&observer);
   sequence->OnScheduled();
 }
 
 void LayerAnimator::SetTransitionDuration(base::TimeDelta duration) {
   if (is_transition_duration_locked_)
     return;
   transition_duration_ = duration;
 }
 
 void LayerAnimator::ClearAnimationsInternal() {
@@ skipping 42 matching lines @@
     const base::WeakPtr<LayerAnimationSequence>& sequence)
     : sequence_(sequence) {
 }
 
 LayerAnimator::RunningAnimation::RunningAnimation(
     const RunningAnimation& other) = default;
 
 LayerAnimator::RunningAnimation::~RunningAnimation() { }
 
 }  // namespace ui