Bug 1519775 - Make one and two-column lists work

[dmose]

Looking for a quick-turnaround review so I can get this (layout-breaking) bug in before the impending export and tidy up individual bits of the lists later. Whoever wants this, feel free to take it!

How to test:

• go to about:config
• search for stream.config
• set that preference to {"enabled":true,"layout_endpoint":"https://getpocket.com/v3/newtab/layout?version=1&consumer_key=40249-e88c401e1b1f2242d9e441c4&layout_variant=dev-test-all"}
• open a new tab

The various trending stories should all be appropriate widths.

Things to note:

• some horizontal rules above or below individual stories may be incorrectly there or incorrectly missing. https://bugzilla.mozilla.org/show_bug.cgi?id=1521119 has been filed.

Known bugs are already captured as dependents of the ds-list-component bug: https://bugzilla.mozilla.org/showdependencytree.cgi?id=1514020&hide_resolved=0

[piatra]

Is this correct? It looks like the extra 16px (592+16) from the 2 column right hand side Trending Stories should go to the 1 column Trending stories (296-16)

[dmose]

I think you're quite possibly right, but I think it's most important to get the fix for this layout bustage into m-c, so I'd propose fixing that in a separate bug.

[piatra]

Ok this looks good to me with the followup fix. Thanks.

[dmose]

https://bugzilla.mozilla.org/show_bug.cgi?id=1521128 filed on the space issue.