Move ObserverList to base namespace.

cc/animation/layer_animation_controller.cc

Index: cc/animation/layer_animation_controller.cc
diff --git a/cc/animation/layer_animation_controller.cc b/cc/animation/layer_animation_controller.cc
index d148a491f80a8f8c237be3e51f7d5ccc92573d59..e6e720f2f230e373505274baf918cff3690fb4c7 100644
--- a/cc/animation/layer_animation_controller.cc
+++ b/cc/animation/layer_animation_controller.cc
@@ -975,7 +975,7 @@ void LayerAnimationController::NotifyObserversOpacityAnimated(
     bool notify_active_observers,
     bool notify_pending_observers) {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr) {
@@ -992,7 +992,7 @@ void LayerAnimationController::NotifyObserversTransformAnimated(
     bool notify_active_observers,
     bool notify_pending_observers) {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr) {
@@ -1009,7 +1009,7 @@ void LayerAnimationController::NotifyObserversFilterAnimated(
     bool notify_active_observers,
     bool notify_pending_observers) {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr) {
@@ -1026,7 +1026,7 @@ void LayerAnimationController::NotifyObserversScrollOffsetAnimated(
     bool notify_active_observers,
     bool notify_pending_observers) {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr) {
@@ -1046,7 +1046,7 @@ void LayerAnimationController::NotifyObserversAnimationWaitingForDeletion() {
 
 bool LayerAnimationController::HasValueObserver() {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     return it.GetNext() != nullptr;
   }
@@ -1055,7 +1055,7 @@ bool LayerAnimationController::HasValueObserver() {
 
 bool LayerAnimationController::HasActiveValueObserver() {
   if (value_observers_.might_have_observers()) {
-    ObserverListBase<LayerAnimationValueObserver>::Iterator it(
+    base::ObserverListBase<LayerAnimationValueObserver>::Iterator it(
         &value_observers_);
     LayerAnimationValueObserver* obs;
     while ((obs = it.GetNext()) != nullptr)