[Win] Only show bell tray icon after a notification.

People who never see a notification should not have their desktop
cluttered with extra status tray icons, so we'll hold off on
creating it until we have a good reason to.

R=jianli@chromium.org
BUG=270688

Review URL: https://chromiumcodereview.appspot.com/22394008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@216827 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/views/message_center/web_notification_tray.cc

@@ -132,7 +132,6 @@ WebNotificationTray::WebNotificationTray()
       should_update_tray_content_(true) {
   message_center_tray_.reset(
       new MessageCenterTray(this, g_browser_process->message_center()));
-  OnMessageCenterTrayChanged();
 }
 
 WebNotificationTray::~WebNotificationTray() {