The font size preference sets a preference to disabled rather than 0.
Rather than save this as 0, it would be useful to store this as a string
given in future it will evolve to have values small, medium, large
Change logic in UserPreferenceRequirement to support non-binary options.
Bug: T346987
Change-Id: I399aa1b1be4a45cab0aa3b8addb482e5af6c5bf3
Generalize LimitedWidthRequirement into a more reusable
UserPreferenceRequirement that can be used by both the limited width feature and
the persistent pinning feature (and possibly others in the future).
* Removes existing logic that checks whether the option is not null. Given that
skin.json sets the default [1], presumably this isn't needed.
* Adds unit test
[1] 65af26a258/skin.json (L163)
Bug: T322051
Change-Id: I7f228cf81a65b2eb22dbe94d2384b6c9f6da91f2
