Creates a JAR which includes: - //webrtc/base:base_java - //webrtc/modules/audio_device:audio_device_java - //webrtc/sdk/android:libjingle_peerconnection_java - //webrtc/sdk/android:libjingle_peerconnection_metrics_default_java The libwebrtc.jar file will be generated at '<output_dir>/lib.java/webrtc/sdk/android/libwebrtc.jar'. BUG=webrtc:6356 Review-Url: https://codereview.webrtc.org/2646443002 Cr-Commit-Position: refs/heads/master@{#16189}