Update docs to use new Gradle version in the engine (#53964)

Updates/corrects steps to update Gradle version used in the engine based on what @gmackall and I did to update the engine's Gradle version in #53574.
 
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: camsim99

tools/gradle/README.md

@@ -1,26 +1,40 @@
-# Updating gradle version used in engine repo
+# Updating the Gradle version used in flutter/engine repo
 
 The instructions in this README explain how to create a CIPD package that
-contains the gradle build-time dependency of the Android embedding of the Engine.
-The Android embedder is shipped to Flutter end-users, but gradle is not.
+contains the [Gradle](https://gradle.org/) build-time dependency of the Android embedding of the engine.
+The Android embedder is shipped to Flutter end-users, but Gradle is not.
 
 ## Requirements
 
-1. If you have a flutter/engine checkout, then you should already have
-[Depot tools](http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up) on your path.
-1. Ensure you have write access for cipd. go/flutter-luci-cipd
-1. Download the new version of gradle then verify the checksum,
-and unzip into a local directory.
+1. Ensure that you have [Depot tools](http://commondatastorage.googleapis.com/chrome-infra-docs/flat/depot_tools/docs/html/depot_tools_tutorial.html#_setting_up)
+on your path. If you have a flutter/engine checkout, then you should already have it on your path.
+2. Ensure that you have write access for CIPD. See go/flutter-luci-cipd for instructions on how to
+request access.
 
-## Update CIPD Steps
-These steps use gradle version 7.5.1 as an example.
+## Steps to download and verify new Gradle version
+These steps use Gradle version 7.5.1 as an example. Please replace 7.5.1 with the actual
+Gradle version that you wish to use.
 
-1. Unzip gradle into a folder `unzip gradle-7.5.1-all.zip`
-1. Authenticate with cipd `cipd auth-login`
-1. Run `cipd create -in gradle-7.5.1 -install-mode copy -tag version:7.5.1 -name flutter/gradle`
-1. Update `engine/src/flutter/DEPS` gradle entry to contain the tag from the command above.
-1. Run `gclient sync` to verify that dependency can be fetched.
+1. Download the new version of Gradle you'd like from [the Gradle website](https://gradle.org/releases/).
+Please download the "complete" version.
+2. Verify the checksum. To do this, first check the checksum of the complete (-all) ZIP Gradle version you
+downloaded from https://gradle.org/release-checksums/. Then, run `shasum -a 256 gradle-7.5.1-all.zip` to
+check the checksum of the Gradle version you downloaded. Verify that the checksum outputted by this
+command and the one from the Gradle website match.
+3. Unzip the Gradle download into a folder by running `unzip gradle-7.5.1-all.zip`.
+
+## Steps to upload new Gradle version to CIPD
+These steps use Gradle version 7.5.1 as an example. Please replace 7.5.1 with the actual
+Gradle version that you downloaded and verified.
+
+1. Authenticate with CIPD by running `cipd auth-login`.
+2. Run `cipd create -in gradle-7.5.1 -install-mode copy -tag version:7.5.1 -name flutter/gradle` to
+upload the new Gradle version to CIPD.
+3. Update the `engine/src/flutter/DEPS` Gradle entry (which should look something like [this](https://github.com/flutter/engine/blob/4caaab9f2502481b606b930abeea4a361022fa16/DEPS#L732-L743))
+to contain the tag from the command above (version:7.5.1).
+4. Run `gclient sync` to verify that the dependency can be fetched.
 
 ## Useful links
-* CIPD gradle https://chrome-infra-packages.appspot.com/p/flutter/gradle/+/
-* Gradle Releases https://gradle.org/releases/
+* CIPD Gradle package: https://chrome-infra-packages.appspot.com/p/flutter/gradle/+/
+* Gradle releases: https://gradle.org/releases/
+* Gradle distribution and wrapper JAR checksum reference: https://gradle.org/release-checksums/