There is a TODO in InspectorCanvas.cpp, to implement buildAction for TypedOMCSSImageValue. It is (as of the time of this bug) located on line 624.
Created attachment 367799 [details]
Created attachment 367810 [details]
Comment on attachment 367810 [details]
Clearing flags on attachment: 367810
Committed r244562: <https://trac.webkit.org/changeset/244562>
All reviewed patches have been landed. Closing bug.