Display menu builder menu from bottom

[sblatz]

For this fenix issue.

We'd like to display the menu builder from the bottom so our most critical menu items are shown even when the whole menu can't be.

┆Issue is synchronized with this Jira Task

[Amejia481]

@sblatz is this issue the same as #2916?

[sblatz]

@Amejia481 No, for this issue we're talking about starting the recylcerview of the menu builder from the bottom. For example, if my device is really short, we want to display C before B in the following menu:
A
B
C

[Amejia481]

@sblatz Do you want to mark some BrowserMenuItem as important to let us know that they should be visible always even though that means moving them up in the list order?

[Amejia481]

Could scroll until the important items are visible could be enough?

[bifleming]

@vesta0 ^^

[vesta0]

@Amejia481

Current state:

Ideal state (so back/forward/refresh is visible):

[vesta0]

Ideally, we also want to have an arrow or something indicating that user can scroll up for more options. @mheubusch for post-mvp.

[pocmo]

@Amejia481 I assume this translates to: For preferred UP direction we scroll all the way down and for preferred DOWN direction we scroll up all the way (or do nothing because that's the default)

[Amejia481]

Just to confirm: @pocmo are you suggesting:

1. Just using the actual orientation property to do a scroll in the opposite direction (UP -> Scroll down and DOWN -> Scroll up)

2. Adding a new property for the consumer to indicate which portion of the menu should be always visible when showing.

If option 1 is the preferred. Is this mixing two concepts? The orientation of the menu and the direction that are we going to do scroll if there is not enough space to show all the items? Is this the expected behavior all cases outside of the toolbar menu use case?

[pocmo]

I was suggesting (1), but yes, I primarily looked at the toolbar and the reference screenshots. For menus in a list like bookmarks that may not be the case and you may always want to show them top to bottom like we do right now. Good catch!

[Amejia481]

As mentioned on mozilla-mobile/fenix#2219 (comment) this is not working properly on Android 5 & 6 devices, let's take a look.

[vesta0]

I am removing MVP blocker since it's only impacting Android 4 & 6.