Show user's avatar in quick comment

We have awesome quick reply feature introduced in %9.2

It looks like that:

As you can see, user's avatar is not shown while ajax's processing.
But we already have user's avatar loaded on the page in the header:

The original avatar's size is loaded. In the header we just set the size to 26:

<img width="26" height="26" class="header-user-avatar" src="https://gitlab.com/uploads/user/avatar/86853/avatar.png" alt="Avatar">

So, if we have avatar already loaded on the page, why not to show it in the quick comment (with gray effect)?

/cc @tauriedavis @kushalpandya

added Accepting Merge Requests label

I like that idea!

@blackst0ne I considered this feature while working on Instant comments, but I didn't wanted to hunt entire page for currently logged-in user's avatar as I wanted it to be part of gon object since it already keeps current_username and current_user_fullname. I see that we have avatar_icon definition (application_helper.rb#L71) is fairly straight-forward and I wonder how tough would it be to populate in gon if we really want to avoid querying DOM for avatar.

@kushalpandya

@winh is working on data storage in frontend: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/11404

Maybe we could use it when it's done?

What do you think?

mentioned in issue #32497 (moved)

assigned to @kushalpandya

mentioned in merge request !11612 (merged)

closed via merge request !11612 (merged)

mentioned in issue gitlab#9948