Android: Don't require RegisterNatives if there are none

base/android/jni_generator/testSingleJNIAdditionalImport.golden

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file is autogenerated by
 //     base/android/jni_generator/jni_generator.py
 // For
 //     org/chromium/foo/Foo
 
 #ifndef org_chromium_foo_Foo_JNI
@@ skipping 21 matching lines @@
 
 extern "C" __attribute__((visibility("default")))
 void Java_org_chromium_foo_Foo_nativeDoSomething(JNIEnv* env, jclass jcaller,
     jobject callback) {
   return DoSomething(env, JavaParamRef<jclass>(env, jcaller),
       JavaParamRef<jobject>(env, callback));
 }
 
 static base::subtle::AtomicWord g_Foo_calledByNative = 0;
 static void Java_Foo_calledByNative(JNIEnv* env, jobject callback) {
-  /* Must call RegisterNativesImpl()  */
   CHECK_CLAZZ(env, Foo_clazz(env),
       Foo_clazz(env));
   jmethodID method_id =
       base::android::MethodID::LazyGet<
       base::android::MethodID::TYPE_STATIC>(
       env, Foo_clazz(env),
       "calledByNative",
 
 "("
 "Lorg/chromium/foo/Bar$Callback;"
@@ skipping 27 matching lines @@
                            kMethodsFooSize) < 0) {
     jni_generator::HandleRegistrationError(
         env, Foo_clazz(env), __FILE__);
     return false;
   }
 
   return true;
 }
 
 #endif  // org_chromium_foo_Foo_JNI