Update CONTRIBUTING doc for the Dart Debug Extension (#1524)

Author: elliette

dwds/debug_extension/CONTRIBUTING.md

@@ -6,13 +6,17 @@
 pub run build_runner build web -o build -r
 ```
 
+This will build to the `/web` directory.
+
 TODO(elliette): Building with DDC no longer works, figure out why. 
 See https://github.com/dart-lang/webdev/issues/1506
 - With DDC:
 
 ```
 pub run build_runner build web -o build
 ```
+
+This will build to the `/build/web` directory. 
 ## Local Development
 
 ### Update `manifest.json`:
@@ -43,8 +47,31 @@ pub run build_runner build web -o build
 * More debugging information can be found in the [Chrome Developers documentation](https://developer.chrome.com/docs/extensions/mv3/devguide/)
 
 
-## Deployment
+## Release process
+
+1. Update the version in `web/manifest.json`, `pubspec.yaml`, and in the `CHANGELOG`. 
+2. Build dart2js: `pub run build_runner build web -o build -r`
+> *At this point, you should manually verify that everything is working by following the steps in [Local Development](#local-development).*
+3. Open a PR to submit the version and build changes.
+4. Once submitted, pull the changes down to your local branch, and create a zip of the `debug_extension/web` directory (NOT `debug_extension/build/web`). 
+5. Rename the zip `version_XX.XX.XX.zip` (eg, `version_1.24.0.zip`) and add it to the go/dart-debug-extension-zips folder 
+> *You must be a Googler to do this. Ask for help if not.*
+6. Go to the [Chrome Web Store Developer Dashboard](https://chrome.google.com/webstore/devconsole).
+7. At the top-right, under Publisher, select dart-bat.
+> *If you don’t see dart-bat as an option, you will need someone on the Dart team to add you to the dart-bat Google group.*
+7. Under Items, select the "Dart Debug Extension".
+8. Go to “Package” then select “Upload new package”.
+> *The first time you do this, you will be asked to pay a $5 registration fee. The registration fee can be expensed.*
+9. Upload the zip file you created in step 4.
+10. Save as draft, and verify that the new version is correct.
+11. Publish. The extension will be published immediately after going through the review process. 
+
+## Rollback process 
+> The Chrome Web Store Developer Dashboard does not support rollbacks. Instead you must re-publish an earlier version. This means that the extension will still have to go through the review process, which can take anywhere from a few hours (most common) to a few days.
+1. Find the previous version you want to rollback to in the go/dart-debug-extension-zips folder. 
+> > *You must be a Googler to do this. Ask for help if not.*
+2. Unzip the version you have chosen, and in `manifest.json` edit the version number to be the next sequential version after the current "bad" version (eg, the bad version is `1.28.0` and you are rolling back to version `1.27.0`. Therefore you change `1.27.0` to `1.29.0`).
+3. Re-zip the directory and rename it to the new version number. Add it to the go/dart-debug-extension-zips folder.
+4. Now, follow steps 6 - 11 in [Release process](#release-process).
+
 
-- Update the version number in `web/manifest.json`.
-- Zip `web/manifest.json`, `web/background.js`, and `dart.png`.
-- Upload the `.zip` to the Chrome Web Store.