Add URL autocompletion in URL bar

[mario]

Background

In order to make working with ABB faster, we'd like to introduce autocompletion of typed URLs in the URL bar.

What to change

As soon as a user starts to type into the URL bar, test if the typed string matches the beginning of a URL which has been visited before and perform the following actions:

1. If the typed string matches a URL that has been visited before and if the last pressed key was not backspace:
   1. Display the remaining characters of the most relevant URL* as autocompleted text as shown in this screenshot (only test and autocomplete the hostname - no full URLs with parameters)
   2. Upon pressing enter, the autocompleted URL is visited
   3. Upon pressing any other key, go back to 1.
2. If the typed string does not match a URL that has been visited before or if the last pressed key was backspace:
   1. Do not display any URL autocompletion as shown in this screenshot

*most relevant URL: in case the typed string matches more than one URL, display the URL that has been visited the most.

Style/Components

Please display and treat the autocompleted text as ordinary selected text:

1. Use the standard font/size/color as well as standard selection highlight color
2. Upon pressing backspace once the selected text is removed as shown in this screenshot
3. Upon pressing backspace more than once the selected text is removed and the previously typed characters are removed one by one

Remark for testers

Please note, that condition 2. ("don't display any URL autocompletion") can be overruled by #4033 which introduces autocompletion for search terms.

[pavelz]

Should be folded into https://issues.adblockplus.org/ticket/4033, see the discussion there.

[mario]

As discussed in #4033, we'll keep the issues separate. We wanted to keep the scope of each issue simple (especially since they're closely related but not dependant on each other) and we wanted to keep testability as simple as possible. Nothing speaks against implementing them both at the same time though.

[pavelz]

@mario ok then please change the issue description to refer to requested behavior of #4033 in point 2. As described in isolation, the QA would fail - an autocompletion will still be displayed.

Also we need a behavior confirmation: a visited URL can naturally be not only the hostname but also path and parameters. Due to today's common practice of request redirections (on behalf of detected user agent, geolocation etc.), such extended URL can be even _the most visited one_. Is this feature asking for autocompleting just the hostname, or the full URL, if it's the most visited one? Our common sense is saying hostname only. On desktop browsers, full URL is always an option, but the selectability and editability on desktop is less awkward experience.

[mario]

ok then please change the issue description to refer to requested behavior of #4033 in point 2.

Changed

Is this feature asking for autocompleting just the hostname, or the full URL, if it's the most visited one? Our common sense is saying hostname only.

Yes, it was intended to only autocomplete the hostname. Changed the Description accordingly.

[scheer]

If the typed string matches the URL that has been visited before and if the last pressed key was not backspace:

• The remaining characters of the most relevant URL are displayed as autocompleted text.
• Upon pressing enter, the autocompleted URL is visited.
• Upon pressing any other key, I was returned to step 1.

If the typed string does not match a URL that has been visited before or if the last pressed key was backspace:

The URL autocompletion is not displayed.

ABB 1.5.0 (1066)
iPhone 6s Plus
iOS 9.3.1