When using the hotkeys "a" (autofit all) & "f" (frame selected) on selected keys of a Timeline in-line curve, the horizontal zoom factor is no longer updated, only the vertical zoom is updated as expected. Both vertical AND horizontal zoom factors need to be updated on a "f" or "a" in-line curve actions.

repro:
- open project
- open "framing" scene
- select Cube and open Timeline
- open Animation tracks in-line curves
- select a subset of keys
- with keys selected, use the "f" & "a" hotkeys to frame, then autofit the curves view...
bug: only vertical zoom factor is updated (AF_bug.gif)
expected: both vertical & horizontal zoom factors are updated (AF_expected.gif)

this is a regression...
repro in...
Version 2018.1.7f1 (4cb482063d12) up to current trunk.

NOT repro in...
Version 2017.4.20f1 (20968fa45e51)
Branch: 2017.4/staging