Replace WebView error pages with custom ones

[pocmo]

Replace WebView error pages with custom ones

[ahunt]

Voila:

[ahunt]

@antlam : do you have any design plans for error pages? I've made a 1:1 copy of the iOS error page for now.

We'll probably need to provide our own error text, if we want to support API 21+ we only get messages like "net::ERR_NAME_NOT_RESOLVED". (API 23+ provides another callback which supplies strings such as "There was a network error." Even that is quite useless, since we know ERROR_HOST_LOOKUP is a DNS error, and not just a network error.)

[antlam]

I was thinking we should just use the same error pages we currently have in Fennec. Minus the "Search" box and maybe the "Enable Wi-Fi" button?

But instead of a light grey background, just use the private browsing grey #363B40 as the background, but use white text.

Thoughts?

[ahunt]

If we use the fennec pages, we could import all the strings 1:1 from fennec (which would save localisation effort), but the search boxes and wifi buttons seem to be hardcoded into the translateable content which makes that a bit harder.

Here's a list of all the strings that fennec uses:
https://dxr.mozilla.org/mozilla-central/source/mobile/locales/en-US/overrides/netError.dtd

[ahunt]

Current status: (it's hard to get a good screenshot with the urlbar also visible because of the scrolling bug)

[antlam]

Nice! @ahunt Can we make the button the same blue that's in our Settings?

[ahunt]

@antlam:

[antlam]

@ahunt final nit - can we remove that / / / / / / / image but keep the same spacing? That is "Server not found" should stay in the same position.

[antlam]

Ship it!