Fix use-after-free in MessageListView.

ui/message_center/views/message_center_view.cc

Index: ui/message_center/views/message_center_view.cc
diff --git a/ui/message_center/views/message_center_view.cc b/ui/message_center/views/message_center_view.cc
index 05db825efbcc0b17a0a7ff65d1165fc37a1c5907..3835cbcbedf083d641a393b81b9a0a45e489e13d 100644
--- a/ui/message_center/views/message_center_view.cc
+++ b/ui/message_center/views/message_center_view.cc
@@ -177,7 +177,7 @@ void MessageCenterView::ClearAllClosableNotifications() {
   if (is_closing_)
     return;
 
-  is_clearing_ = true;
+  is_clearing_all_notifications_ = true;
   UpdateButtonBarStatus();
   SetViewHierarchyEnabled(scroller_, false);
   message_list_view_->ClearAllClosableNotifications(
@@ -185,7 +185,7 @@ void MessageCenterView::ClearAllClosableNotifications() {
 }
 
 void MessageCenterView::OnAllNotificationsCleared() {
-  is_clearing_ = false;
+  is_clearing_all_notifications_ = false;
   SetViewHierarchyEnabled(scroller_, true);
   button_bar_->SetCloseAllButtonEnabled(false);
 
@@ -639,7 +639,7 @@ void MessageCenterView::SetVisibilityMode(Mode mode, bool animate) {
 
 void MessageCenterView::UpdateButtonBarStatus() {
   // Disables all buttons during animation of cleaning of all notifications.
-  if (is_clearing_) {
+  if (is_clearing_all_notifications_) {
     button_bar_->SetSettingsAndQuietModeButtonsEnabled(false);
     button_bar_->SetCloseAllButtonEnabled(false);
     return;