Android: Replace webrtc_jni namespace with nested jni namespace

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

Index: webrtc/sdk/android/src/jni/classreferenceholder.cc
diff --git a/webrtc/sdk/android/src/jni/classreferenceholder.cc b/webrtc/sdk/android/src/jni/classreferenceholder.cc
index 5b309d08d3fa3d4d6db84bcd5370399f39dd4cd1..c79f936ff57109d30079624440635b2c3f52fa29 100644
--- a/webrtc/sdk/android/src/jni/classreferenceholder.cc
+++ b/webrtc/sdk/android/src/jni/classreferenceholder.cc
@@ -11,7 +11,8 @@
 
 #include "webrtc/sdk/android/src/jni/jni_helpers.h"
 
-namespace webrtc_jni {
+namespace webrtc {
+namespace jni {
 
 // ClassReferenceHolder holds global reference to Java classes in app/webrtc.
 class ClassReferenceHolder {
@@ -153,4 +154,5 @@ jclass FindClass(JNIEnv* jni, const char* name) {
   return g_class_reference_holder->GetClass(name);
 }
 
-}  // namespace webrtc_jni
+}  // namespace jni
+}  // namespace webrtc