[cronet_http] Apply relevant rules with the ProGuard (#1204)

diff --git a/pkgs/cronet_http/CHANGELOG.md b/pkgs/cronet_http/CHANGELOG.md
index fd2acca..25d0df3 100644
--- a/pkgs/cronet_http/CHANGELOG.md
+++ b/pkgs/cronet_http/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 1.3.1-wip
+
+* Add relevant rules with the ProGuard to avoid runtime exceptions.
+
 ## 1.3.0
 
 * Add integration to the
diff --git a/pkgs/cronet_http/android/consumer-rules.pro b/pkgs/cronet_http/android/consumer-rules.pro
index 00f4f3e..00a7e57 100644
--- a/pkgs/cronet_http/android/consumer-rules.pro
+++ b/pkgs/cronet_http/android/consumer-rules.pro
@@ -1 +1,4 @@
 -keep class io.flutter.plugins.cronet_http.** { *; }
+-keep class java.net.URL { *; }
+-keep class java.util.concurrent.Executors { *; }
+-keep class org.chromium.net.** { *; }
diff --git a/pkgs/cronet_http/example/android/app/build.gradle b/pkgs/cronet_http/example/android/app/build.gradle
index dfd7427..add4718 100644
--- a/pkgs/cronet_http/example/android/app/build.gradle
+++ b/pkgs/cronet_http/example/android/app/build.gradle
@@ -73,5 +73,6 @@
     implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.8.0"))
     // ""com.google.android.gms:play-services-cronet" is only present so that
     // `jnigen` will work. Applications should not include this line.
+    // The version should be synced with `pkgs/cronet_http/android/build.gradle`.
     implementation "com.google.android.gms:play-services-cronet:18.0.1"
 }
diff --git a/pkgs/cronet_http/pubspec.yaml b/pkgs/cronet_http/pubspec.yaml
index 4a3da88..8d7c5d2 100644
--- a/pkgs/cronet_http/pubspec.yaml
+++ b/pkgs/cronet_http/pubspec.yaml
@@ -1,5 +1,5 @@
 name: cronet_http
-version: 1.3.0
+version: 1.3.1-wip
 description: >-
   An Android Flutter plugin that provides access to the Cronet HTTP client.
 repository: https://github.com/dart-lang/http/tree/master/pkgs/cronet_http