* gnu/build/chromium-extension.scm (make-crx): Delay with-imported-modules
until the builder code.
(crx->chromium-json): Remove needless define* while at it.
* gnu/build/chromium-extension.scm (chromium-json->profile-object): Remove
variable.
(file-sha256): New variable.
(make-chromium-extension): Rename OUTPUT parameter to prevent conflict.
Adjust other variable names for clarity.
[inputs]: Clear.
[arguments]: Inline and simplify the final transformation with a gexp.
