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

base/android/base_jni_registrar.cc

Index: base/android/base_jni_registrar.cc
diff --git a/base/android/base_jni_registrar.cc b/base/android/base_jni_registrar.cc
index 06b01495c58bfbe24c3135373f679d2507579af2..bcebd31ffe50bba66e204ba0f644043fc66ddadf 100644
--- a/base/android/base_jni_registrar.cc
+++ b/base/android/base_jni_registrar.cc
@@ -30,5 +30,8 @@ bool RegisterJni(JNIEnv* env) {
                                arraysize(kBaseRegisteredMethods));
 }
 
+// Add the methods to be registered for APK unit tests.
+ADD_JNI_REGISTRATION_METHODS_FOR_TESTS(kBaseRegisteredMethods)
+
 }  // namespace android
 }  // namespace base