Use gradle dependencies for Cronet extension

This also allows us to distribute the extension via jCenter

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=207874626

RELEASENOTES.md

@@ -2,6 +2,7 @@
 
 ### dev-v2 (not yet released) ###
 
+* Distribute Cronet extension via jCenter.
 * Add `AudioListener` for listening to changes in audio configuration during
   playback ([#3994](https://github.com/google/ExoPlayer/issues/3994)).
 * Improved seeking support:

core_settings.gradle

@@ -30,6 +30,7 @@ include modulePrefix + 'extension-flac'
 include modulePrefix + 'extension-gvr'
 include modulePrefix + 'extension-ima'
 include modulePrefix + 'extension-cast'
+include modulePrefix + 'extension-cronet'
 include modulePrefix + 'extension-mediasession'
 include modulePrefix + 'extension-okhttp'
 include modulePrefix + 'extension-opus'
@@ -51,6 +52,7 @@ project(modulePrefix + 'extension-flac').projectDir = new File(rootDir, 'extensi
 project(modulePrefix + 'extension-gvr').projectDir = new File(rootDir, 'extensions/gvr')
 project(modulePrefix + 'extension-ima').projectDir = new File(rootDir, 'extensions/ima')
 project(modulePrefix + 'extension-cast').projectDir = new File(rootDir, 'extensions/cast')
+project(modulePrefix + 'extension-cronet').projectDir = new File(rootDir, 'extensions/cronet')
 project(modulePrefix + 'extension-mediasession').projectDir = new File(rootDir, 'extensions/mediasession')
 project(modulePrefix + 'extension-okhttp').projectDir = new File(rootDir, 'extensions/okhttp')
 project(modulePrefix + 'extension-opus').projectDir = new File(rootDir, 'extensions/opus')
@@ -58,9 +60,3 @@ project(modulePrefix + 'extension-vp9').projectDir = new File(rootDir, 'extensio
 project(modulePrefix + 'extension-rtmp').projectDir = new File(rootDir, 'extensions/rtmp')
 project(modulePrefix + 'extension-leanback').projectDir = new File(rootDir, 'extensions/leanback')
 project(modulePrefix + 'extension-jobdispatcher').projectDir = new File(rootDir, 'extensions/jobdispatcher')
-
-if (gradle.ext.has('exoplayerIncludeCronetExtension')
-        && gradle.ext.exoplayerIncludeCronetExtension) {
-    include modulePrefix + 'extension-cronet'
-    project(modulePrefix + 'extension-cronet').projectDir = new File(rootDir, 'extensions/cronet')
-}

extensions/cronet/README.md

@@ -5,37 +5,22 @@ The Cronet extension is an [HttpDataSource][] implementation using [Cronet][].
 [HttpDataSource]: https://google.github.io/ExoPlayer/doc/reference/com/google/android/exoplayer2/upstream/HttpDataSource.html
 [Cronet]: https://chromium.googlesource.com/chromium/src/+/master/components/cronet?autodive=0%2F%2F
 
-## Build instructions ##
+## Getting the extension ##
 
-To use this extension you need to clone the ExoPlayer repository and depend on
-its modules locally. Instructions for doing this can be found in ExoPlayer's
-[top level README][]. In addition, it's necessary to get the Cronet libraries
-and enable the extension:
+The easiest way to use the extension is to add it as a gradle dependency:
 
-1. Find the latest Cronet release [here][] and navigate to its `Release/cronet`
-   directory
-1. Download `cronet_api.jar`, `cronet_impl_common_java.jar`,
-   `cronet_impl_native_java.jar` and the `libs` directory
-1. Copy the three jar files into the `libs` directory of this extension
-1. Copy the content of the downloaded `libs` directory into the `jniLibs`
-   directory of this extension
-1. In your `settings.gradle` file, add
-   `gradle.ext.exoplayerIncludeCronetExtension = true` before the line that
-   applies `core_settings.gradle`.
-1. In all `build.gradle` files where this extension is linked as a dependency,
-   add
-   ```
-   android {
-    compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_8
-        targetCompatibility JavaVersion.VERSION_1_8
-    }
-   }
-   ```
-   to enable Java 8 features required by the Cronet library.
+```gradle
+implementation 'com.google.android.exoplayer:extension-cronet:2.X.X'
+```
+
+where `2.X.X` is the version, which must match the version of the ExoPlayer
+library being used.
+
+Alternatively, you can clone the ExoPlayer repository and depend on the module
+locally. Instructions for doing this can be found in ExoPlayer's
+[top level README][].
 
 [top level README]: https://github.com/google/ExoPlayer/blob/release-v2/README.md
-[here]: https://console.cloud.google.com/storage/browser/chromium-cronet/android
 
 ## Using the extension ##
 

extensions/cronet/build.gradle

@@ -19,14 +19,10 @@ android {
     buildToolsVersion project.ext.buildToolsVersion
 
     defaultConfig {
-        minSdkVersion project.ext.minSdkVersion
+        minSdkVersion 16
         targetSdkVersion project.ext.targetSdkVersion
     }
 
-    sourceSets.main {
-        jniLibs.srcDirs = ['jniLibs']
-    }
-
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
@@ -34,9 +30,7 @@ android {
 }
 
 dependencies {
-    api files('libs/cronet_api.jar')
-    implementation files('libs/cronet_impl_common_java.jar')
-    implementation files('libs/cronet_impl_native_java.jar')
+    api 'org.chromium.net:cronet-embedded:66.3359.158'
     implementation project(modulePrefix + 'library-core')
     implementation 'com.android.support:support-annotations:' + supportLibraryVersion
     testImplementation project(modulePrefix + 'library')
@@ -47,3 +41,9 @@ ext {
     javadocTitle = 'Cronet extension'
 }
 apply from: '../../javadoc_library.gradle'
+
+ext {
+    releaseArtifact = 'extension-cronet'
+    releaseDescription = 'Cronet extension for ExoPlayer.'
+}
+apply from: '../../publish.gradle'

extensions/cronet/jniLibs/README.md

-Copy folders containing architecture specific .so files here.

extensions/cronet/libs/README.md

-Copy cronet.jar and cronet_api.jar here.