Good catch, let's add the same behavior for extension.

Sebastien, thank you for the confirmation.

Megumi-san, could you take a look? (it's ok to do this after current items you're working are finished.) Thank you.

Thank you! I'll do this after finishing my current task.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b5e4d9905f3df7553a166812d59f4e168b7d9fff

commit b5e4d9905f3df7553a166812d59f4e168b7d9fff
Author: Megumi Hattori <megumihattori@google.com>
Date: Mon Feb 26 04:15:46 2018

Add inline settings and enable block of Chrome extension notification.

Previously, only web notifications have the inline settings and can be
blocked depending the settings. This CL also applies this feature to
Chrome extension notifications.

This CL adds the inline settings on the Chrome extension notification
and enables users to choose whether to block the notification or not.

Due to this implementation, a gear icon for the inline settings is
also added on the notification.

BUG= 810622 

Change-Id: I6197167d2c587cd40a1e92b81a5bba5d3057820f
Reviewed-on: https://chromium-review.googlesource.com/923877
Commit-Queue: Megumi Hattori <megumihattori@google.com>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#539067}
[modify] https://crrev.com/b5e4d9905f3df7553a166812d59f4e168b7d9fff/chrome/browser/extensions/api/notifications/extension_notification_handler.cc
[modify] https://crrev.com/b5e4d9905f3df7553a166812d59f4e168b7d9fff/chrome/browser/extensions/api/notifications/extension_notification_handler.h
[modify] https://crrev.com/b5e4d9905f3df7553a166812d59f4e168b7d9fff/chrome/browser/extensions/api/notifications/notifications_api.cc