Android: Replace webrtc_jni namespace with nested jni namespace

webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc

Index: webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc
diff --git a/webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc b/webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc
index 5a94c5b52d71e1f42b178788e04403c1fa59bebe..89a348f4c1ba39fba3a8077b0cd9251ad5e6e106 100644
--- a/webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc
+++ b/webrtc/sdk/android/src/jni/pc/rtpreceiverobserver_jni.cc
@@ -12,7 +12,8 @@
 
 #include "webrtc/sdk/android/src/jni/pc/java_native_conversion.h"
 
-namespace webrtc_jni {
+namespace webrtc {
+namespace jni {
 
 void RtpReceiverObserverJni::OnFirstPacketReceived(
     cricket::MediaType media_type) {
@@ -29,4 +30,5 @@ void RtpReceiverObserverJni::OnFirstPacketReceived(
   CHECK_EXCEPTION(jni) << "error during CallVoidMethod";
 }
 
-}  // namespace webrtc_jni
+}  // namespace jni
+}  // namespace webrtc