Allowing better focus styling through adding "lostFocus" to %messageClasses%

[mathuaerknedam]

There are certain styling limitations with the way focus indicators are currently implemented. For example, #12145 points out how the default focus indicator can obscure message text and the SmoothOp page describes how the focus indicator can overlap the mention indicator. Also, it's difficult to integrate the focus indicator into a message style's "look".

This proposal is that when focus is lost adium would add "lostFocus" to %messageClasses% for the next message. When the next focus change is made Adium would need to find the existing "lostFocus" remove it, and add it to new location. Zac further suggests requiring a message style info.plist key to enable the functionality.

Here's a IRC transcript of Zac's response:

10:13:26 zac ‣ sort of possible yes	
10:15:08 zac ‣ it's a good idea for 1.4.1 but not for 1.4	
10:15:18 zac ‣ we can add an info.plist entry for "supports focus recognition" and do that

[Zachary West <zacw@…>]

(In  bb4935318350) Instead of inserting a <hr/> when we lose focus, which ends up breaking more than you'd expect, add a message class for the next message. Fixes #13300.

This removes the "Show Focus Lines" preference (always a good thing), and always inserts the mark in the scrollbar. It will be up to the style to implement the "focus" class to show the location. All previous messages of class "focus" will have "focus" removed when focus is lost again.

[Zachary West <zacw@…>]

(In  7ff6b3f336d6) Instead of inserting a <hr/> when we lose focus, which ends up breaking more than you'd expect, add a message class for the next message. Fixes #13300.

This removes the "Show Focus Lines" preference (always a good thing), and always inserts the mark in the scrollbar. It will be up to the style to implement the "focus" class to show the location. All previous messages of class "focus" will have "focus" removed when focus is lost again.

[Zachary West <zacw@…>]

(In  2b6390521141) Don't add a focus class for messages in the active chat. Refs #13300.

[Zachary West <zacw@…>]

(In  a2f78c3401b9) Don't add a focus class for messages in the active chat. Refs #13300.