Added Docs For Updating to a New Java Version in CI (flutter#166159)

Added docs for updating to a new Java version in CI. Also added
instructions on uploading new Java version pacakges to CIPD.

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
on [Discord].

<!-- Links -->
[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md

Author: jesswrd

docs/platforms/android/New-Android-version.md

@@ -66,6 +66,19 @@ In the engine, you may follow [Upgrading Engine's Android API version](https://g
 - Example Framework PR: <https://github.com/flutter/flutter/pull/152498>.
 - Example Engine PR: <https://github.com/flutter/engine/pull/54186>.
 
+##### Update Java Version in CI (Only for Java LTS Release)
+
+Every few years Java releases a new Java LTS (long-term support) version, which typically
+becomes the industry standard for a few years. As users adopt the new Java LTS version, either
+directly or as part of the latest Android SDK, we want to update our CI to test against the new Java version
+to identify and address potential compatibility issues.
+
+Upload the new Java Version package to CIPD following the instructions [here](/docs/platforms/android/Uploading-New-Java-Version-to-CIPD.md).
+
+Update the usages of the current Java version to the new Java version in CI.
+
+- Example PR: <https://github.com/flutter/flutter/pull/165210>.
+
 #### Update documentation
 
 Update documentation page to indicate the new API is tested

docs/platforms/android/Uploading-New-Java-Version-to-CIPD.md

@@ -0,0 +1,72 @@
+# Uploading New Java Version to CIPD
+
+We store the Java Version package on CIPD for use on CI. For more information read the internal
+docs [here](http://go/luci-cipd).
+
+Some links in the instructions below are Google-internal.
+
+## Steps
+
+### Request Access to CIPD
+
+1. Request temporary write access to upload packages to CIPD
+   via http://go/flutter-luci-cipd#requesting-write-read-access-to-cipd-packages.
+
+2. Wait about 5-30 minutes for access rights to sync. To check if your rights have synced, see if
+   you are a member of this
+   group [here](https://chrome-infra-auth.appspot.com/auth/groups/google%[email protected]).
+
+### Download the New Java Version and Set Up for CIPD Upload
+
+3. Download the new Java version via OpenJDK (not Oracle's Java for licensing/legal
+   reasons) [here](https://openjdk.org/projects/jdk/) for the following platforms:
+   linux-amd64(aka x64), mac-arm64, mac-amd64, and windows-amd64.
+
+4. Download the latest Java version from
+   CIPD [here](https://chrome-infra-packages.appspot.com/p/flutter/java/openjdk) for the following
+   platforms: linux-amd64(aka x64), mac-arm64, mac-amd64, and windows-amd64.
+
+5. Unzip the new Java version and the latest version.
+
+6. Add a file titled `openjdk.cipd.yaml` at the top-level directory. Copy the contents below into
+   the file and replace contents in <> for your new Java version package:
+   ```sh
+    package: flutter/java/openjdk/<platform-architecture>
+    description: OpenJDK <java_version> for <platform>
+    install_mode: copy
+    data:
+    # This directory contains Java <platform-architecture> to be used in automated tests.
+    - dir: .
+   ```
+
+   Note: `linux-amd64` is an example of `<platform-architecture>`
+
+7. Ensure the file/directory structure of the new Java version package to be uploaded is the same as
+   the structure at the top-level of the latest from CIPD.
+   This involves potentially deleting contents of the top-level directory.
+
+### Upload to CIPD
+
+8. To run CIPD commands, please run this command:
+
+    ```sh
+    cipd auth-login
+    ```
+
+9. To upload the new Java version to CIPD, please run this command:
+
+    ```sh
+     cipd create -in <path_to_new_java_version_package>  -name flutter/java/openjdk/<platform-architecture> -tag version:<java_version>
+    ```
+
+   Note: Please check you have the correct name, tags, package structure before uploading to CIPD
+   because deleting the package on CIPD is difficult.
+
+10. Check to see if your new Java version has successfully uploaded to CIPD by clicking on the
+    relevant platform [here](https://chrome-infra-packages.appspot.com/p/flutter/java/openjdk).
+
+### Troubleshooting CIPD (Optional)
+
+If you accidentally uploaded the incorrect package to CIPD, you can delete the tag using these
+instructions [here](go/flutter-luci-playbook#remove-duplicated-cipd-tags).
+Then, re-upload the correct Java version pacakge to CIPD.