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 a5f848dd2d5ba4c5677a80ac331c28aa2977a012..11a5c780200bed299bda27e957ad95ede45cc157 100644
--- a/ash/system/tray/system_tray.cc
+++ b/ash/system/tray/system_tray.cc
@@ -619,6 +619,9 @@ void SystemTray::SetShelfAlignment(wm::ShelfAlignment alignment) {
   if (notification_bubble_) {
     notification_bubble_.reset();
     UpdateNotificationBubble();
+    // UpdateWebNotifications() should be called in UpdateNotificationBubble().
+  } else if (!hide_notifications_) {
+    UpdateWebNotifications();
   }
 }