Most notably:
* Move some code snippets from the outer …TemplateWidget to
the inner …SelectWidget, without introducing new
dependencies.
* Move all knowledge about the item class
…OutlineParameterWidget class into …SelectWidget.
* Some more self-documenting method names for event handlers.
* Avoid the somewhat ambiguous variable name "checkbox" in
favor of "item". That's how it's named in the upstream OOUI
…SelectWidget.
This is extracted from the following patch Ibd94c39. The
difference is that the following patch adds a new dependency:
The …SelectWidget gets to know the template model. This patch
here contains all changes that are possible without this new
dependency.
Bug: T288827
Change-Id: I187f313c84424b28005d9276cb1356029f9ebb75
