Android: Replace webrtc_jni namespace with nested jni namespace

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

Index: webrtc/sdk/android/src/jni/jni_helpers.cc
diff --git a/webrtc/sdk/android/src/jni/jni_helpers.cc b/webrtc/sdk/android/src/jni/jni_helpers.cc
index 6e2360811d9cc45bae1c17f9a6d18b0cf17bc7dd..bb9bbf47036275e202df37777479744079d49392 100644
--- a/webrtc/sdk/android/src/jni/jni_helpers.cc
+++ b/webrtc/sdk/android/src/jni/jni_helpers.cc
@@ -17,7 +17,8 @@
 
 #include "webrtc/sdk/android/src/jni/classreferenceholder.h"
 
-namespace webrtc_jni {
+namespace webrtc {
+namespace jni {
 
 static JavaVM* g_jvm = nullptr;
 
@@ -385,4 +386,5 @@ bool Iterable::Iterator::AtEnd() const {
   return jni_ == nullptr || IsNull(jni_, iterator_);
 }
 
-}  // namespace webrtc_jni
+}  // namespace jni
+}  // namespace webrtc