The transition is started once the sheet is released. If the user is dragging the sheet to close it, release or close are the only signals that make sense for starting the toolbar transition, because if the user is still touching the toolbar they could start dragging it back up.

When the back button is pressed, we could add some logic to detect that the sheet is animating to its peek state and start the transition. I don't think this would be too hard, but it would need to act in coordination with the (still to be added) logic dictating whether we go back to the previous tab or the tab switcher. 

I think this should be P3 polish.

Got it. I'll keep it as P2 for now to see if Chris has any thoughts about better animations and then we can reprioritize once we have a better idea of what we want. (e.g. not animating in the Chrome Home button in the button-trigger condition)

Can we disable the sliding the toolbar buttons when Chrome Home is the NTP?

The toolbar buttons need to be shown when going from NTP -> tab switcher and NTP -> regular tab, so I'm not sure what disabling the animation would help with?

We would disable sliding in the toolbar buttons when going from NTP to tab switcher since they are visually different.

The tab switcher toolbar and regular toolbar are the same Android View (long-term we've been talking about changing this but it's out-of-scope for M61), so we can't just disable the toolbar buttons sliding to achieve the right visual effect. We would need to write more custom animation code.

Ah I see. So we can't just cross fade from Chrome Home to tab switcher toolbar as we do with the rest of the toolbar? If so, happy to de-pri this one to P3.

Unfortunately we currently cannot.

In an in-flight patch I am starting the transition from the normal toolbar to the tab switcher toolbar sooner so that it feels a bit less abrupt so hopefully that takes care of the "P2" polish and further improvements can be "P3".

The Chrome Home experiment has ended; closing obsolete bug.