Add JSFiddle to cloudbuild

This is a little more complicated than other builds because we need
the webassembly binaries out fo skia-wasm-release when we do the webpack
step and we can't run docker (e.g. docker run skia-wasm-release cp foo.wasm)
inside of the skia-public/infra:prod image.

To get around this limitation, we add a step that extracts the binaries to
a /workspace/wasm-products folder (which persists between steps) and mount
that folder as a volume for when we make the jsfiddle output. The only tricky
thing is that we must manually mount the /workspace/__jsfiddle_staging folder
as a volume too, or it doesn't persist to the build step.

Something similar will be needed for skottie.skia.org after
https://skia-review.googlesource.com/c/buildbot/+/169700 lands.

Bug: skia:
Change-Id: Iec05fff7231a28ecfa209489e5c75a9621b334d2
Reviewed-on: https://skia-review.googlesource.com/c/169821
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
1 file changed