[google_sign_in] document web usage

packages/google_sign_in/google_sign_in/CHANGELOG.md

@@ -1,6 +1,7 @@
-## NEXT
+## 5.0.3
 
 * Fixed links in `README.md`.
+* Added documentation for usage on the web.
 
 ## 5.0.2
 

packages/google_sign_in/google_sign_in/README.md

@@ -6,7 +6,8 @@ _Note_: This plugin is still under development, and some APIs might not be
 available yet. [Feedback](https://github.com/flutter/flutter/issues) and
 [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!
 
-## Android integration
+## Platform integration
+### Android integration
 
 To access Google Sign-In, you'll need to make sure to
 [register your application](https://firebase.google.com/docs/android/setup).
@@ -23,7 +24,7 @@ Make sure you've filled out all required fields in the console for
 [OAuth consent screen](https://console.developers.google.com/apis/credentials/consent).
 Otherwise, you may encounter `APIException` errors.
 
-## iOS integration
+### iOS integration
 
 1. [First register your application](https://firebase.google.com/docs/ios/setup).
 2. Make sure the file you download in step 1 is named
@@ -57,7 +58,7 @@ Otherwise, you may encounter `APIException` errors.
 <!-- End of the Google Sign-in Section -->
 ```
 
-### iOS additional requirement
+#### iOS additional requirement
 
 Note that according to
 https://developer.apple.com/sign-in-with-apple/get-started, starting June 30,
@@ -70,12 +71,31 @@ The Flutter Favorite
 [sign_in_with_apple](https://pub.dev/packages/sign_in_with_apple) plugin could
 be an option.
 
+### Web integration
+
+<!-- Copied from https://developers.google.com/identity/sign-in/web/sign-in on May 11, 2021-->
+#### Create authorization credentials
+
+1. Go to the [Credentials page](https://console.developers.google.com/apis/credentials).
+1. Click **Create credentials > OAuth client ID**.
+1. Select the **Web application** application type.
+1. Name your OAuth 2.0 client and click **Create**.
+
+After configuration is complete, take note of the client ID that was created. You will need the client ID to complete the next steps. (A client secret is also created, but you need it only for server-side operations.)
+
+#### Specify your app's client ID
+
+In your app's `web/index.html` file, specify the client ID you created for your app in the Google Developers Console with the `google-signin-client_id` meta element.
+
+```html
+<meta name="google-signin-client_id" content="YOUR_CLIENT_ID.apps.googleusercontent.com">
+```
 ## Usage
 
 ### Import the package
 
 To use this plugin, follow the
-[plugin installation instructions](https://pub.dev/packages/google_sign_in#pub-pkg-tab-installing).
+[plugin installation instructions](https://pub.dev/packages/google_sign_in/install).
 
 ### Use the plugin
 
@@ -114,4 +134,3 @@ Future<void> _handleSignIn() async {
 
 Find the example wiring in the
 [Google sign-in example application](https://github.com/flutter/plugins/blob/master/packages/google_sign_in/google_sign_in/example/lib/main.dart).
-

packages/google_sign_in/google_sign_in/pubspec.yaml

@@ -2,7 +2,7 @@ name: google_sign_in
 description: Flutter plugin for Google Sign-In, a secure authentication system
   for signing in with a Google account on Android and iOS.
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_sign_in/google_sign_in
-version: 5.0.2
+version: 5.0.3
 
 flutter:
   plugin: