Add a method for getting the native factory from PeerConnectionFactory.

Bug: webrtc:8662
Change-Id: Icfe09e82737e1b700e469afde00c4f0923bbeb42
Reviewed-on: https://webrtc-review.googlesource.com/39516
Reviewed-by: Anders Carlsson <andersc@webrtc.org>
Commit-Queue: Sami Kalliomäki <sakal@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21628}

sdk/android/api/org/webrtc/PeerConnectionFactory.java

@@ -342,6 +342,11 @@ public class PeerConnectionFactory {
     nativeInvokeThreadsCallbacks(nativeFactory);
   }
 
+  /** Returns a pointer to the native webrtc::PeerConnectionFactoryInterface. */
+  public long getNativePeerConnectionFactory() {
+    return nativeGetNativePeerConnectionFactory(nativeFactory);
+  }
+
   private static void printStackTrace(Thread thread, String threadName) {
     if (thread != null) {
       StackTraceElement[] stackTraces = thread.getStackTrace();
@@ -415,4 +420,5 @@ public class PeerConnectionFactory {
       long factory, Object localEGLContext, Object remoteEGLContext);
   private static native void nativeInvokeThreadsCallbacks(long factory);
   private static native void nativeFreeFactory(long factory);
+  private static native long nativeGetNativePeerConnectionFactory(long factory);
 }

sdk/android/src/jni/pc/peerconnectionfactory.cc

@@ -490,5 +490,12 @@ static void JNI_PeerConnectionFactory_SetVideoHwAccelerationOptions(
                 remote_egl_context);
 }
 
+static jlong JNI_PeerConnectionFactory_GetNativePeerConnectionFactory(
+    JNIEnv* jni,
+    const JavaParamRef<jclass>&,
+    jlong native_factory) {
+  return jlongFromPointer(factoryFromJava(native_factory));
+}
+
 }  // namespace jni
 }  // namespace webrtc