Build WebRTC with data channel only.

webrtc/sdk/android/src/jni/null_video_jni.cc

+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <jni.h>
+
+#include "webrtc/base/scoped_ref_ptr.h"
+#include "webrtc/sdk/android/src/jni/classreferenceholder.h"
+
+namespace cricket {
+class WebRtcVideoEncoderFactory;
+class WebRtcVideoDecoderFactory;
+}  // namespace cricket
+
+namespace webrtc_jni {
+
+class MediaCodecVideoEncoderFactory;
+class MediaCodecVideoDecoderFactory;
+class SurfaceTextureHelper;
+
+cricket::WebRtcVideoEncoderFactory* CreateVideoEncoderFactory() {
+  return nullptr;
+}
+
+cricket::WebRtcVideoDecoderFactory* CreateVideoDecoderFactory() {
+  return nullptr;
+}
+
+jobject GetJavaSurfaceTextureHelper(
+    rtc::scoped_refptr<SurfaceTextureHelper> surface_texture_helper) {
+  return nullptr;
+}
+
+}  // namespace webrtc_jni