Android Allows nested namespace in @JNINamespace annotation.

base/android/jni_generator/sample_for_tests.cc

 // Copyright (c) 2012 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.
 
 #include "base/android/jni_android.h"
 #include "base/android/scoped_java_ref.h"
 
 // The main purpose of this is to ensure sample_for_tests_jni.h
 // compiles and the functions declared in it as expected.
 
 using base::android::AttachCurrentThread;
 using base::android::ScopedJavaLocalRef;
 
-namespace content {
+namespace base {
+namespace android {
 
 class CPPClass {
  public:
   class InnerClass {
    public:
     jdouble MethodOtherP0(JNIEnv* env, jobject obj) {
       return 0.0;
     }
   };
 
   void Destroy(JNIEnv* env, jobject obj) {
     delete this;
   }
 
   jint Method(JNIEnv* env, jobject obj) {
     return 0;
   }
 
   ScopedJavaLocalRef<jstring> InnerMethod(JNIEnv* env, jobject obj) {
     return ScopedJavaLocalRef<jstring>();
   }
 };
 
-} // namespace content
+} // namespace android
+} // namespace base
 
 #include "jni/SampleForTests_jni.h"
 
 int main() {
   // On a regular application, you'd call AttachCurrentThread(). This sample is
   // not yet linking with all the libraries.
   JNIEnv* env = /* AttachCurrentThread() */ NULL;
 
   // This is how you call a java static method from C++.
-  bool foo = content::Java_SampleForTests_staticJavaMethod(env);
+  bool foo = base::android::Java_SampleForTests_staticJavaMethod(env);
 
   // This is how you call a java method from C++. Note that you must have
   // obtained the jobject somehow.
   jobject my_java_object = NULL;
-  int bar = content::Java_SampleForTests_javaMethod(env, my_java_object, 1, 2);
+  int bar = base::android::Java_SampleForTests_javaMethod(
+      env, my_java_object, 1, 2);
 
   return 0;
 }