Implement support for silent notifications.

ui/message_center/notification.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/notification.h"
 
 #include "base/logging.h"
 #include "ui/message_center/notification_delegate.h"
 #include "ui/message_center/notification_types.h"
 
@@ skipping 12 matching lines @@
 ButtonInfo::ButtonInfo(const base::string16& title)
  : title(title) {
 }
 
 RichNotificationData::RichNotificationData()
     : priority(DEFAULT_PRIORITY),
       never_timeout(false),
       timestamp(base::Time::Now()),
       progress(0),
       should_make_spoken_feedback_for_popup_updates(true),
-      clickable(true) {}
+      clickable(true),
+      silent(false) {}
 
 RichNotificationData::RichNotificationData(const RichNotificationData& other)
     : priority(other.priority),
       never_timeout(other.never_timeout),
       timestamp(other.timestamp),
       context_message(other.context_message),
       image(other.image),
       small_image(other.small_image),
       items(other.items),
       progress(other.progress),
@@ skipping 114 matching lines @@
           icon,
           base::string16()  /* display_source */,
           NotifierId(NotifierId::SYSTEM_COMPONENT, system_component_id),
           RichNotificationData(),
           new HandleNotificationClickedDelegate(click_callback)));
   notification->SetSystemPriority();
   return notification.Pass();
 }
 
 }  // namespace message_center