Update cached height for popup notifications after shelf alignment changes

ash/system/tray/system_tray.cc

Index: ash/system/tray/system_tray.cc
diff --git a/ash/system/tray/system_tray.cc b/ash/system/tray/system_tray.cc
index 13f41a198d1702141e85ea5e4eae6a8a47f2ff2f..28b3392d221dc39a3a6726d4c79763869c3c715c 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -624,6 +624,9 @@ void SystemTray::SetShelfAlignment(wm::ShelfAlignment alignment) {
   if (notification_bubble_) {
     notification_bubble_.reset();
     UpdateNotificationBubble();
+    // UpdateWebNotifications() should be called in UpdateNotificationBubble().
+  } else if (!hide_notifications_) {
+    UpdateWebNotifications();
   }
 }