Remove balloon notification code. The last user was the Linux GTK port but that's deleted now.

chrome/browser/notifications/message_center_notification_manager.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 "chrome/browser/notifications/message_center_notification_manager.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/prefs/pref_registry_simple.h"
 #include "base/prefs/pref_service.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/notifications/desktop_notification_service_factory.h"
 #include "chrome/browser/notifications/fullscreen_notification_blocker.h"
 #include "chrome/browser/notifications/message_center_settings_controller.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/screen_lock_notification_blocker.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_finder.h"
@@ skipping 64 matching lines @@
 #endif
   registrar_.Add(this,
                  chrome::NOTIFICATION_FULLSCREEN_CHANGED,
                  content::NotificationService::AllSources());
 }
 
 MessageCenterNotificationManager::~MessageCenterNotificationManager() {
   message_center_->RemoveObserver(this);
 }
 
+void MessageCenterNotificationManager::RegisterPrefs(
+    PrefRegistrySimple* registry) {
+  registry->RegisterBooleanPref(prefs::kMessageCenterShowedFirstRunBalloon,
+                                false);
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 // NotificationUIManager
 
 void MessageCenterNotificationManager::Add(const Notification& notification,
                                            Profile* profile) {
   if (Update(notification, profile))
     return;
 
   DesktopNotificationServiceFactory::GetForProfile(profile)->
       ShowWelcomeNotificationIfNecessary(notification);
@@ skipping 387 matching lines @@
 
 MessageCenterNotificationManager::ProfileNotification*
     MessageCenterNotificationManager::FindProfileNotification(
         const std::string& id) const {
   NotificationMap::const_iterator iter = profile_notifications_.find(id);
   if (iter == profile_notifications_.end())
     return NULL;
 
   return (*iter).second;
 }