+ Amy: Is it a toast or a snack bar ? I'd like to make sure we're using the right terminology.

Snackbar is correct :) 

From Material: 
Snackbars contain a single line of text directly related to the operation performed. They may contain a text action, but no icons.

Toasts (Android only) are primarily used for system messaging. They also display at the bottom of the screen, but may not be swiped off-screen.

Usage
Only one snackbar may be displayed at a time. Each snackbar may contain a single action, neither of which may be “Dismiss” or “Cancel.”

Behavior
Snackbars animate upwards from the bottom edge of the screen.

Snackbar specs
Action button: Roboto Medium 14sp, all-caps text
Mobile height: 48dp (single-line), 80dp (multi-line)
Desktop snackbar height: 48dp

More on the topic for your etymological pleasure: https://material.googleplex.com/components/snackbars-toasts.html#

Thanks, Amy :) !

I looked at how to implement this and it turns out that doing it properly requires quite a bit of work.
The main issue is that the *color* of the button wouldn't just be synced with the reading list anymore (which was simple and elegant), it would also have to take into account the state of the snackbar.

Implementing this involves changing the BrowserViewController (because of the snackbar), the Toolbar (because of the ⋮ button), and possibly moving some of the ReadingList code out of */toolbar/ to /components/reading_list/ (which would require new @protocol and a new @class).

So what I am saying is that this will definitely not be in M57.

M-58, sounds good thanks!

jif@ is no longer on the team. Releasing his bugs.

Is this still relevant with the new Bijou design? 

With Bijou, the snackbars visually block the overflow menu's icon, so the animation as described here won't be visible. We might want to revisit this since we are redesigning the snackbars, not to black the overflow menu. For now at least we won't continue implementing this.