support display: -webkit-flex and -webkit-flex: 1

[mykmelez]

@brendandahl: This should enable display: -webkit-flex and -webkit-flex: 1, and it does fix the layout of the navigation bar in the sample browser, but the iframe overlaps the navigation bar, partially obscuring it, when the app is first started:

That problem goes away (and stays away) as soon as I resize the app window. Another problem is a horizontal scrollbar at the bottom of the app window, which is persistent, regardless of window size.

I'm not sure if either of these are problems with this branch in particular, Gecko's support for flex in general, or perhaps the app itself.

[brendandahl]

Perhaps we need -webkit-flex-direction too?

[brendandahl]

I haven't check it after all of our changes, but I was previously able to get it to display correctly by doing:

65c65
<   -webkit-box-sizing: border-box;
---
>   box-sizing: border-box;
69,70c69
<   display: -webkit-flex;
<   -webit-flex-direction: column;
---
>   display: flex;
74,76c73,74
<   -webkit-flex: 1;
<   display: -webkit-flex;
<   -webit-flex-direction: column;
---
>   flex: 1;
>   display: flex;
80c78
<   -webkit-flex: 1;
---
>   flex: 1;
101,103c99,101
<   -webkit-flex: 1;
<   display: -webkit-flex;
<   -webit-flex-direction: row;
---
>   flex: 1;
>   display: flex;
>   flex-direction: row;
117,118c115,116
<   -webkit-box-sizing: border-box;
<   -webkit-flex: 1;
---
>   box-sizing: border-box;
>   flex: 1;
239d236
< 

[brendandahl]

Actually this branch+master seems to good for me. (no resizing) https://www.dropbox.com/s/semd3ir55po4t6m/Screenshot%202016-06-07%2011.53.32.png?dl=0

[mykmelez]

Perhaps we need -webkit-flex-direction too?

I was going to do that but then noticed that the app actually misspells all its -webkit-flex-direction properties as -webit-flex-direction, so those shouldn't be applied by in Chromium either.

[mykmelez]

Actually this branch+master seems to good for me. (no resizing)

Is that with or without your modifications to the app itself?

[mykmelez]

I haven't check it after all of our changes, but I was previously able to get it to display correctly by doing:

It looks like these changes only set flex-direction: row, but that's the initial value of the property, per https://developer.mozilla.org/en-US/docs/Web/CSS/flex-direction, so I would think they'd need to do the opposite and set flex-direction: column when needed.

[brendandahl]

Is that with or without your modifications to the app itself?

Without my modifications.

[mykmelez]

Without my modifications.

Hunh, strange, I wonder why you and I are seeing different results!

[mykmelez]

@brendandahl found out from @dholbert that these aliases landed recently in mozilla-central, so #78 merged from upstream to acquire them.

[mykmelez]

FWIW, I still see the first-paint issue after merging from upstream. I filed https://github.com/mozilla/positron/issues/79 on it.