Add a way for JNI registrars to specify methods to be registered for tests.

net/android/net_jni_registrar.cc

Index: net/android/net_jni_registrar.cc
diff --git a/net/android/net_jni_registrar.cc b/net/android/net_jni_registrar.cc
index b475cac391ff715368291d275abbdc906bbdf180..e636bc6bd0a1e8de9f96b1d5bf44b57331b8ff9a 100644
--- a/net/android/net_jni_registrar.cc
+++ b/net/android/net_jni_registrar.cc
@@ -25,5 +25,8 @@ bool RegisterJni(JNIEnv* env) {
       env, kNetRegisteredMethods, arraysize(kNetRegisteredMethods));
 }
 
+// Add the methods to be registered for APK unit tests.
+ADD_JNI_REGISTRATION_METHODS_FOR_TESTS(kNetRegisteredMethods)
+
 }  // namespace android
 }  // namespace net