Fix crash when removing all notifications by "Clear all" button.

ui/message_center/message_center_impl.cc

 // Copyright (c) 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 "ui/message_center/message_center_impl.h"
 
 #include <algorithm>
 #include <deque>
 #include <memory>
 #include <utility>
@@ skipping 638 matching lines @@
   if (!notifications.empty()) {
     notification_cache_.Rebuild(
         notification_list_->GetVisibleNotifications(blockers_));
   }
 }
 
 void MessageCenterImpl::RemoveAllNotifications(bool by_user, RemoveType type) {
   bool remove_pinned = (type == RemoveType::ALL);
 
   const NotificationBlockers& blockers =
-      (type == RemoveType::ALL ? NotificationBlockers() /* empty blockers */
-                               : blockers_ /* use default blockers */);
+      remove_pinned ? NotificationBlockers() /* empty blockers */
+                    : blockers_;             /* use default blockers */
 
   const NotificationList::Notifications notifications =
       notification_list_->GetVisibleNotifications(blockers);
   std::set<std::string> ids;
   for (auto* notification : notifications) {
     if (!remove_pinned && notification->pinned())
       continue;
 
     ids.insert(notification->id());
     scoped_refptr<NotificationDelegate> delegate = notification->delegate();
@@ skipping 228 matching lines @@
 }
 
 void MessageCenterImpl::EnableChangeQueueForTest(bool enable) {
   if (enable)
     notification_queue_.reset(new internal::ChangeQueue());
   else
     notification_queue_.reset();
 }
 
 }  // namespace message_center