Since abb36e3cb, we no longer rely on the cli to set up ServiceWorker, but do it
manually as part of `yarn build`. When using `ng serve`, registering the
ServiceWorker fails, because we haven't created `ngsw-manifest.json` nor copied
`worker-basic.min.js` into dist.
This commit works around this, by only registering the service worker in
production mode (which is what the cli does too).
Caveat:
It is not possible to enable ServiceWorker with `ng serve`/`yarn start` and
using the `--prod` flag will try to register it, but fail because the necessary
files (`ngsw-manifest.json` and `worker-basic.min.js`) will not be available.
(As a work-around, you can use `yarn build` and serve the files in `dist/` with
`yarn http-server -- dist -p 4200`.)
This shouldn't change anything. But it's interesting that we used to have this import
that seemed bogus, but there were no compilation or rutime errors.
All the docs related files (docs-app, doc-gen, content, etc)
are now to be found inside the `/aio` folder.
The related gulp tasks have been moved from the top level
gulp file to a new one inside the `/aio` folder.
The structure of the `/aio` folder now looks like:
```
/aio/
build/ # gulp tasks
content/ #MARKDOWN FILES for devguides, cheatsheet, etc
devguides/
cheatsheets/
transforms/ #dgeni packages, templates, etc
src/
app/
assets/
content/ #HTML + JSON build artifacts produced by dgeni from /aio/content.
#This dir is .gitignored-ed
e2e/ #protractor tests for the doc viewer app
node_modules/ #dependencies for both the doc viewer builds and the dgeni stuff
#This dir is .gitignored-ed
gulpfile.js #Tasks for generating docs and building & deploying the doc viewer
```
Closes#14361
Georgios Kalpakas
Alex Rickabaugh
Igor Minar
Pete Bacon Darwin