cronet: add build.gradle and script for Cronet deps

RELEASING.md

@@ -65,6 +65,7 @@ $ VERSION_FILES=(
   build.gradle
   android-interop-testing/app/build.gradle
   core/src/main/java/io/grpc/internal/GrpcUtil.java
+  cronet/build.gradle
   examples/build.gradle
   examples/pom.xml
   examples/android/helloworld/app/build.gradle

cronet/.gitignore

@@ -0,0 +1 @@
+libs/

cronet/README.md

@@ -44,3 +44,11 @@ ExperimentalCronetEngine engine =
     new ExperimentalCronetEngine.Builder(context /* Android Context */).build();
 ManagedChannel channel = CronetChannelBuilder.forAddress("localhost", 8080, engine).build();
 ```
+
+## Running the tests with Gradle
+
+To run the gRPC Cronet tests with the included `gradle.build` file, you will
+need to first download the Cronet jars and place them in the `libs/` directory.
+The included script, `cronet_deps.sh`, will do this automatically but requires
+the [gsutil](https://cloud.google.com/storage/docs/gsutil) tool to access files
+from Google Cloud Storage.

cronet/build.gradle

@@ -0,0 +1,60 @@
+apply plugin: 'com.android.library'
+
+description = "gRPC: Cronet Android"
+
+buildscript {
+    repositories {
+        google()
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.0.1'
+    }
+}
+
+allprojects {
+    repositories {
+        jcenter()
+        mavenLocal()
+    }
+}
+
+android {
+    compileSdkVersion 27
+    defaultConfig {
+        minSdkVersion 14
+        targetSdkVersion 27
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        debug {
+            minifyEnabled false
+        }
+        release {
+            minifyEnabled true
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    testOptions {
+        unitTests {
+            includeAndroidResources = true
+        }
+    }
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+}
+
+dependencies {
+    implementation 'io.grpc:grpc-core:1.10.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+    testImplementation 'io.grpc:grpc-testing:1.10.0-SNAPSHOT' // CURRENT_GRPC_VERSION
+
+    implementation files('libs/cronet_api.jar')
+    implementation files('libs/cronet_impl_common_java.jar')
+
+    testImplementation 'junit:junit:4.12'
+    testImplementation 'org.mockito:mockito-core:1.10.19'
+    testImplementation "org.robolectric:robolectric:3.5.1"
+}

cronet/cronet_deps.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+mkdir libs
+gsutil cp gs://chromium-cronet/android/64.0.3254.0/Release/cronet/cronet_api.jar libs/
+gsutil cp gs://chromium-cronet/android/64.0.3254.0/Release/cronet/cronet_impl_common_java.jar \
+    libs/

cronet/proguard-rules.pro

@@ -0,0 +1,13 @@
+# Add project specific ProGuard rules here.
+# By default, the flags in this file are appended to flags specified
+# in $ANDROID_HOME/tools/proguard/proguard-android.txt
+# You can edit the include path and order by changing the proguardFiles
+# directive in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# Add any project specific keep options here:
+
+-dontwarn org.chromium.**
+-dontnote org.chromium.**

cronet/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="io.grpc.cronet" />